Phenomenon Of Splitting Research Articles

A detailed seismic anisotropy study during the 2011–2012 unrest period in the Santorini Volcanic Complex

The Santorini Volcanic Complex (SVC) is an area in the Southern Aegean (Greece) which has been characterized by low seismicity rates for the last decades, especially in the Santorini Caldera where they have been very low until 2010. This pattern changed completely in February 2011, when intense microseismic activity was initiated within the Caldera. During the manual analysis of the events, the shear-wave splitting phenomenon was observed, revealing the existence of an anisotropic upper crust in the SVC area. A detailed anisotropy study has been conducted using 231 events within the shear-wave window that fulfilled the selection criteria. The polarization direction of the fast shear-wave, the time-delay between the two split shear-waves and the source polarization direction were calculated after visual inspection, using both the polarigram and the hodogram representations. This procedure, applied for eight local stations, resulted in the determination of 340 splitting parameters. The obtained mean anisotropy directions are not homogeneous, revealing a complex regime in the activated area. Nevertheless, these results are explained by the APE model, related to the stress-sensitive behavior of fluid-saturated microcracked rocks. A detailed analysis of the temporal evolution of both the time-delay and anisotropy direction was carried out. The time-delays measured in the “band-1” window exhibit gradual increase and sudden drop that can be related to imminent bursts of seismicity, as well as to the major Mw=5.1 and 5.2 events which took place about 40km SW of Santorini on 26 and 27 January 2012, respectively. On the other hand, no significant temporal variations or 90° flips of the Sfast polarization direction were observed.

Analysis on the Structure and Performance of Austenitic Stainless Steel Cladding Layer

MIG welding overlaid austenitic stainless steel on low alloy Q345B. The overlay cladding comprises a transition layer and corrosion resistant layer. Overlaying specimens of transition layer with different thicknesses were prepared. The mechanical properties of joints were tested by micro-hardness, bending test and other methods. The results showed that the mechanical properties of specimen with ER309L welding wire as transition layer did not have splitting phenomena after being bended. There were no cracks. However, the specimen without transition layer had small crack or tiny cracks. When the transition layer thickness is changed, the performance of overlay cladding is essentially unchanged. The organizations of overlay cladding in four groups of specimens are similar, which are composed of austenite and ferrite, and ferrite was mostly distributed in strips and blocks.

Frequency Splitting Phenomena of Magnetic Resonant Coupling Wireless Power Transfer

In magnetic resonant coupling wireless power transfer (WPT) system, the frequency splitting phenomena have a vital influence on the output power. This paper mainly focuses on the frequency splitting of two-coil and three-coil WPT. First, the frequency characteristics of transfer power and system efficiency of the two-coil WPT are analyzed by circuit theory. In addition, the magnetic field distribution of the two splitting frequencies is simulated to analyze which frequency is better for the operating frequency. Second, considering the reference resistance of RF power, the frequency splitting of two-coil and three-coil WPT is analyzed. Finally, the critical coupling, which determines the over coupled region, of two-coil and three-coil WPT is derived. Meanwhile, we propose a tuned frequency method according to the numerical results. In addition, the transfer power can be kept at a relatively constant level in the over coupled region.

Observation of valley-dependent beams in photonic graphene.

Valley-dependent propagation of light in an artificial photonic hexagonal lattice, akin to electrons in graphene, is investigated in microwave regime. Both numerical and experimental results show that the valley degeneracy in the photonic graphene is broken when the frequency is away from the Dirac point. The peculiar anisotropic wave transport property due to distinct valleys is analyzed using the equifrequency contours. More interestingly, the valley-dependent self-collimation and beam splitting phenomena are experimentally demonstrated with the armchair and zigzag interfaces, respectively. Our results confirm that there are two inequivalent Dirac points that lead to two distinct valleys in photonic graphene, which could be used to control the flow of light and might be used to carry information in valley polarized beam splitter, collimator or guiding device.

Stochastic Bifurcations and Noise-Induced Chaos in a Dynamic Prey–Predator Plankton System

We consider the stochastic Truscott–Brindley dynamical model of the interacting populations of prey and predator. We study a new phenomenon of the stochastic cycle splitting. In a zone of Canard cycles, using the stochastic sensitivity function technique, we find a critical value of the parameter corresponding to the supersensitive cycle. In the neighborhood of this critical value, a comparative parametrical analysis of the phenomenon of the stochastic cycle splitting is performed. It is shown that the bifurcation of the stochastic cycle splitting is accompanied by the noise-induced chaotization.

A Critical Review of Wireless Power Transfer via Strongly Coupled Magnetic Resonances

Strongly coupled magnetic resonance (SCMR), proposed by researchers at MIT in 2007, attracted the world’s attention by virtue of its mid-range, non-radiative and high-efficiency power transfer. In this paper, current developments and research progress in the SCMR area are presented. Advantages of SCMR are analyzed by comparing it with the other wireless power transfer (WPT) technologies, and different analytic principles of SCMR are elaborated in depth and further compared. The hot research spots, including system architectures, frequency splitting phenomena, impedance matching and optimization designs are classified and elaborated. Finally, current research directions and development trends of SCMR are discussed.

Tele‐Seismic PS‐Wave Splitting from the Basement in the Capital Area of China

AbstractAn important advantage of tele‐seismic PS‐waves is carrying the anisotropy information of media beneath seismic stations. This paper uses the analysis method of three‐component PS‐wave splitting to analyze the basement PS‐waves based on the high‐precision tele‐seismic data of Capital Area Seismic Network (CASN) from 2002 to 2003. The purpose is to acquire the PS‐wave splitting parameters beneath the seismic stations, including polarization of fast PS‐waves and the time delays of fast and slow PS‐waves, and to reveal the shallow crust anisotropy beneath the seismic stations. The results show that this method preserves the original information of the wave field, which allows us to analyze the features of PS‐wave splitting. The tele‐seismic PS‐waves from the basement recorded by short period stations have the advantage of less noise and higher SNR, and have splitting phenomena commonly. Besides we find the time delay of fast and slow PS‐waves is beyond our expectation, which has average values of time delay 0.1∼0.2 s. This research can be compared with shear‐wave splitting, which would help recognize anisotropy and stress state of crust and study tectonics and seismic activity.

Band split in multiband all-dielectric left-handed metamaterials

In this paper, we propose and fabricate multiband all-dielectric left-handed metamaterials (ADMs) in the X-band microwave regime. The ADMs are fabricated by a combination of dielectric resonators in shapes of cubes and rods. The ADMs can exhibit two left-handed pass bands while the rods contact the sidewalls of the waveguide. A band split phenomenon is observed when the boundary conditions of dielectric rods change. The two pass bands can diverge into three left-handed pass bands when the rods do not contact the waveguide. By using field analysis and dielectric resonator theory, we prove that the boundary conditions have a strong influence on the resonant modes of the rod resonator, which plays key roles in left-handedness. The boundary tuned resonant modes can broaden our ways of designing new types of metamaterials.

Plasticity of hexagonal systems: Split slip modes and inverse Peierls relation inα-Ti

The plasticity of hexagonal titanium is reexamined based on the split slip modes phenomenon, revealing the existence of subslip modes in prismatic and pyramidal hcp slip systems. The energetics of dislocation emission and motions were described using all-dimension relaxed atomic models of crystal slip, calculated with density functional theory. The proposed computational methodology is based on the generalized stacking fault energy concept and respects all elastic effects arising within dislocation nucleation. As a result, improved accuracy has been obtained with regard to ductility prediction and a breach has been discovered in the fundamental Peierls-Nabarro rule. This approach is essential for the Rice and Peierls-Nabarro models and can be used as an effective tool for ductility predictions when designing new hexagonal alloys.

Magnetic and Mössbauer Studies on Mixed-Metal Cyano-Bridged Compounds Gu<sub>n</sub>M<sub>1.5-n</sub>[Fe(CN)<sub>6</sub>]·xH<sub>2</sub>O(M=Ni, Gu)

Mixed-metal cyano-bridged compounds GunM1.5-n[Fe (CN)6]·xH2O(M=Ni, Gu) have been prepared by co-precipitation. The magnetic results show that the compound Cu0.75Ni0.75[Fe (CN)6]·xH2O is ferromagnetic, undergoes a paramagnetic to the ferromagnetic transition temperature at 21.77 K. The paramagnetic curie temperature θ, residual magnetization Mr, and coercive field Hcare different from bimetallic Prussian Blue analogues Ni3[Fe (CN)6]2·xH2O and Cu3[Fe (CN)6]2· xH2O. As to Cu3[Fe (CN)6]2·xH2O, the magnetic susceptibilities follow the Curie-Weiss law and the Weiss paramagnetic Curie temperature is 19.1 K. The Mossbauer spectrum at room temperature reveals a doublet with the isomer shift parameter (-0.03 mm/s) and quadrupole splitting (QS= 1.09 mm/s). As the sample was cooled down to 16K, the magnetic splitting phenomenon was detected in the compound.

Gas–liquid two-phase flow equal distribution using a wheel distributor

A specially designed wheel distributor is proposed to extract equal small fraction (7%) of gas and liquid from the total gas–liquid mixture. The distributor mainly consists in a wheel, splitting channels and two fluid receiving rooms. With the rotation of the wheel, the total flow is conducted alternately into main flow loop and sample loop through their corresponding splitting channels. The fraction of gas and liquid taken off is determined by the structure of the wheel distributor and independent of gas and liquid flow rate, flow patterns and the wheel rotation velocity. Experiments were carried out in an air–water two-phase flow loop to verify the feasibility of the device. The inner diameter of the test loop was 50mm. the superficial gas velocity varied from 4.0m/s to 22m/s, and the superficial liquid velocity was within the range of 0.018–0.2m/s. The flow pattern occurred during the experiments involved wave flow, slug flow and annular flow. Experimental results were in good agreement with the theoretical value. The advantages of the proposed distributor are that the fluid in the branch is extracted from the whole cross section instead of a local place and the phase splitting phenomenon is substantially eliminated.

Migraine trait symptoms in migraine with and without aura

The aim of the study was to determine whether various transient sensory and neuropsychological symptoms (SNS) were associated with migraine using a custom questionnaire. In this hypothesis-generating case-control study, the frequencies of transient SNS in 219 patients with migraine (149 without aura and 70 with aura) were compared with 161 age- and sex-matched healthy controls using a custom questionnaire. Patients from a tertiary academic headache center in Hamburg were contacted by regular mail. Healthy controls without a history of migraine were recruited by means of a screening questionnaire and consecutively approached by e-mail. The presence of both migraine and aura was associated with significantly higher frequencies of autokinesis, metamorphopsia, dyschromatopsia, cinematographic vision, illusionary visual spread, and synesthesia (for all comparisons: corrected p < 0.05). Double vision, inverted 2- and 3-dimensional vision, and altered perception of body weight and size were found more often in patients with migraine without aura than in those with aura. In contrast, aura was associated with the occurrence of visual splitting and corona phenomenon (for all comparisons: corrected p < 0.05). No relevant association with migraine was found for micropsia and macropsia, teleopsia and pelopsia, inverted vision, out-of-body experience, Doppelgänger phenomenon, complex visual hallucinations, and altered perception of body position in space. The observed SNS seem to belong to a physiologic spectrum of multisensory phenomena. Some of these phenomena were significantly accentuated in patients with migraine and may therefore be termed migraine trait symptoms. However, these results will have to be confirmed in a prospective study with face-to-face interviews.

Interplay of Rashba/Dresselhaus spin splittings probed by photogalvanic spectroscopy –A review

The paper reviews the interplay of Rashba/Dresselhaus spin splittings in various two‐dimensional systems made of zinc‐blende III–V, wurtzite, and SiGe semiconductors. We discuss the symmetry aspects of the linear and cubic in electron wavevector spin splitting in heterostructures prepared on (001)‐, (110)‐, (111)‐, (113)‐, (112)‐, and (013)‐ oriented substrates and address the requirements for suppression of spin relaxation and realization of the persistent spin helix state. In experimental part of the paper, we overview experimental results on the interplay of Rashba/Dresselhaus spin splittings probed by photogalvanic spectroscopy: The method based on the phenomenological equivalence of the linear‐in‐wavevector spin splitting and several photogalvanic phenomena.

Utility of dissociated intrinsic hand muscle atrophy in the diagnosis of amyotrophic lateral sclerosis.

The split hand phenomenon refers to predominant wasting of thenar muscles and is an early and specific feature of amyotrophic lateral sclerosis (ALS). A novel split hand index (SI) was developed to quantify the split hand phenomenon, and its diagnostic utility was assessed in ALS patients. The split hand index was derived by dividing the product of the compound muscle action potential (CMAP) amplitude recorded over the abductor pollicis brevis and first dorsal interosseous muscles by the CMAP amplitude recorded over the abductor digiti minimi muscle. In order to assess the diagnostic utility of the split hand index, ALS patients were prospectively assessed and their results were compared to neuromuscular disorder patients. The split hand index was significantly reduced in ALS when compared to neuromuscular disorder patients (P<0.0001). Limb-onset ALS patients exhibited the greatest reduction in the split hand index, and a value of 5.2 or less reliably differentiated ALS from other neuromuscular disorders. Consequently, the split hand index appears to be a novel diagnostic biomarker for ALS, perhaps facilitating an earlier diagnosis.

March 2014: This Month in JoVE - Food-Related Motivation, Pathogens in the Deli, Diagnosing ALS, and Bioengineering Cells into Patterns

Here's a look at what's coming up in the March 2014 issue of JoVE: The Journal of Visualized Experiments. This month, we have a special culinary focus with food-related articles from various JoVE sections. In JoVE Environment, we have a method for tracking the spread of the bacterium Listeria monocytogenes. This foodborne pathogen contaminates all kinds of foods in the retail environment - including dairy, eggs, produce, meat, and fish. According to the Centers for Disease Control and Prevention (CDC), Listeria sickens around 1,600 people in the United States every year, and is the 3rd leading cause of death related to food poisoning. Many cases of Listeria-related illness can be traced to contaminated deli meats, especially those sliced by retailers. To study how this potentially deadly pathogen spreads in retail environments, Sirsat et al. simulate bacterial contamination of deli meat using a fluorescent compound that glows under black light, focusing on the deli slicer itself as a critical point of Listeria cross contamination. This method can be adapted to study other microbial pathogens in retail and industrial environments, and facilitate sanitary practices in multiple settings. In a culinary article from JoVE's Behavior section, we examine what drives us to eat. Besides the obvious impulse of hunger, the rewarding aspects of food can drive certain behaviors, especially overeating. Ziauddeen et al. use several methods to examine food-related motivation. In one experiment, subjects have to physically work to win food or non-food rewards. In another experiment, they test whether subliminal images of a food reward can affect an individual's willingness to work for it. In a third experiment, subjects assign monetary values on various foods, which yields quantitative measures of food-related rewards. These methods can be used to study the effectiveness of anti-obesity treatments that alter the reward value of food. In JoVE Clinical and Translational Medicine, we feature an article on amyotrophic lateral sclerosis (ALS, commonly known as Lou Gehrig's disease). In this degenerative neuromuscular disease, muscles become paralyzed when motor neurons disconnect from muscle fibers at the neuromuscular junction (NMJ). An early symptom that is specific to ALS is the split hand phenomenon, or the preferential weakness of a specific group of hand muscles, while other hand muscles are spared. Menon and Vucic demonstrate a novel method of obtaining split hand index scores. To do this, they record maximal motor responses from three hand muscles. By comparing the responses of various patients, our authors demonstrate how this index can distinguish ALS from other neuromuscular diseases. In JoVE Bioengineering, many applications involve growing cells on synthetic surfaces. Therefore, a common bioengineering research goal is to understand the mechanisms of cell adhesion and patterning on synthetic materials. Hughes et al. have developed a method for photolithographically printing silicon dioxide chips with paralene-C. Cells specifically adhere to the paralene-C while being repelled by the silicon dioxide. This technique has allowed patterning of a broad range of cell types, including HEK 293 cells, primary human glioma-derived stem-like cells, and 3T3 L1 cells You've just had a sneak peek of the March 2014 issue of JoVE. Visit the website to see the full-length articles, plus many more, in JoVE: The Journal of Visualized Experiments.

NOISE-INDUCED OSCILLATING BISTABILITY AND TRANSITION TO CHAOS IN FITZHUGH–NAGUMO MODEL

Stochastic dynamics of the FitzHugh–Nagumo (FHN) neuron model in the limit cycles zone is studied. For weak noise, random trajectories are concentrated in the small neighborhood of the unforced deterministic cycle. As the noise intensity increases, in the Canard-like cycles zone of the FHN model, a bundle of the stochastic trajectories begins to split into two parts. This phenomenon is investigated using probability density functions for the distribution of random trajectories. It is shown that the intensity of noise generating this splitting bifurcation significantly depends on the stochastic sensitivity of cycles. Using the stochastic sensitivity function (SSF) technique, we find a critical value of the parameter corresponding to the supersensitive cycle. For the neighborhood of this critical value, a comparative parametrical analysis of the phenomenon of the stochastic cycle splitting is performed. To predict the splitting bifurcation and estimate a threshold value of the noise intensity, we use a confidence domains method based on SSF. A phenomenon of the noise-induced chaotization is studied. We show that P-bifurcation of the splitting of stochastic cycles implies a D-bifurcation of a noise-induced chaotization.

Efficient performance optimisation of wireless power transmission using genetic algorithm

Wireless power transfer (WPT) systems using a coupled magnetic resonance have to overcome the frequency splitting phenomenon for a certain distance in order to achieve the best efficiency. In this reported work, a simple and effective method is demonstrated to overcome the frequency splitting for an optimal efficiency, regardless of the distance variation while maintaining the single desired operating frequency. Then, the systems do not need complicated frequency adjustment systems to track the split frequency. For the proposed method, the equivalent circuit parameters of the WPT system are extracted to overcome the frequency splitting by using the genetic algorithm (GA). Then, two adjustable capacitors are added at the source and the load with the optimal values calculated by the GA, again, at the desired operating frequency for the optimal efficiency.

ELECTRONIC TRANSPORT PROPERTIES OF TRANSITION METAL (Cu, Fe) PHTHALOCYANINES CONNECTING TO V-SHAPED ZIGZAG GRAPHENE NANORIBBONS

Using nonequlilibrium Green's functions in combination with the density-functional theory, we investigate the spin transport properties of molecular junction based on metal ( Cu , Fe ) phthalocyanines between V-shaped zigzag-edged graphene nanorribons. The results show that the electronic transport properties mainly depend on the center transition metal. The negative differential resistance behaviors and spin splitting phenomenon can be observed.

Comparison investigation on natural convection of cold water near its density maximum in annular enclosures with complex configurations

In order to compare the characteristics of natural convection of cold water near its density maximum in annular enclosures with various complex configurations, a series of numerical simulations were carried out using the finite volume method. The effects of the Rayleigh number, the density inversion parameter and the aspect ratio on natural convective flow and heat transfer were analyzed, and the variations of local and average Nusselt numbers were discussed in these enclosures. The results show that the flow pattern depends mainly on geometrical configurations of the enclosures, the Rayleigh number and the density inversion parameter. The Rayleigh–Bénard convection cells appear in the top or bottom region for the R-C, T-C, E-S and E-T configurations at a large Rayleigh number. With the increase of the aspect ratio, the number of the vortex in the flow cell increases and the cell splitting phenomenon happens at a large aspect ratio in the R-C, D-C, T-C, E-S and E-T configurations. The heat transfer correlations for various configurations have been proposed, and the enclosure with the best heat transfer performance among various configurations is assured based on the simulation results.

A Planar Magnetically Coupled Resonant Wireless Power Transfer System Using Printed Spiral Coils

A fully planar wireless power transfer (WPT) system via strongly coupled magnetic resonances is presented. In it, both the transmitter and the receiver are planarized with the use of coplanar printed spiral coils (PSCs) and a printed loop. An equivalent circuit model of the proposed planar WPT system is derived to facilitate the design, and a flowchart is provided for the optimization of the system with given size constraints. To realize high peak power transfer efficiency, the quality factor of individual loop or resonator, the mutual coupling between resonators, and the frequency splitting phenomenon of the system are analyzed in addition to the effect of the input impedance of the system on the transmission efficiency. Furthermore, parallel current paths are created by applying auxiliary strips to the backside of the substrates and connecting to the prime resonators using vias to decrease the resistance and to increase the quality factor of the PSC resonators, and this in turn further improves the transfer efficiency of the proposed planar WPT system. The measured results show that the proposed WPT system is able to provide a stable wireless power transfer with up to 81.68% efficiency at a distance of 10 cm. The planar structure and the high transfer efficiency make the proposed design a suitable candidate for wireless power transfer of small portable electronic devices.