External Modes Research Articles

Optical feedback-induced dynamics and nonclassical photon statistics of semiconductor microcavity laser

We study a coherently driven semiconductor laser cavity containing a single quantum dot(QD) (as gain medium) with optical feedback under Markovian approximation. We have obtained coupled operator equations for the model Hamiltonian using standard input-output formalism of cavity-QED and have found that these equations do not have any finite steady state solutions. We have also used an exact numerical framework based on Matlab platform qotoolbox, to compute the temporal dynamics of the mean excitation number of laser cavity mode under high feedback coupling regime. We have further studied the photon correlations of both the cavity mode as well as external feedback mode to feedback identify the laser parameters and coupling strength that give the nonclassical sub-Poissonian photon statistics. This work is useful for coherent control of photon statistics and photon correlations in the semiconductor laser with optical feedback.

Roman Wall Paintings: Characterisation of Plaster Coats Made of Clay Mud

This paper reports on the mineralogical characterisation of samples of wall paintings from various Roman sites in Lombardy (Italy), revealing recurrent types of stratigraphy. One of the stratigraphic samples analysed was found to be a particular kind of plaster: a three-coat work featuring two coats made of clay mud, found in the site of Santa Maria alla Porta (area of the Imperial Palace of Milan—first century CE). The fragments were analysed using optical microscopy on thin sections, X-ray diffraction, scanning electron microscopy with an energy-dispersive spectrometer and infrared spectroscopy, also in non-invasive external reflection mode (7500–375 cm−1). The most interesting feature found was the finish coat made of clay mud (illite, chlorite, kaolinite and fine quartz) with a few coarse clasts and linear cavities. This clay coat was the first example ever detected in Roman Lombardy and was used in combination with a thin painted coat made of clay mud with coarse clasts together with a blue pigment (Egyptian blue) and a render coat made of lime associated with lithic clasts (sand). Our findings brought to light a particular construction technique, since in the historical sources clay is only recommended for daubing on reeds and as a render coat.

Runaway electron generation and loss in EAST disruptions

Runaway currents have been detected during unintended disruptions in the circular plasma with the limiter configuration in the Experimental Advanced Superconducting Tokamak (EAST). The runaway electron (RE) plateau can carry up to 80% of the pre-disruption plasma current. The highest runaway currents correspond to the lowest loop voltage, which is contrary to the observations made in most tokamaks. This anomalous behavior is attributed to the acceleration of the pre-existing wave resonant suprathermal electrons by lower hybrid waves during the disruption decay phase. Two distinct types of RE-related relaxation phenomena, distinguished on the basis of the amplitude of the magnetic fluctuations, have been found during the disruptions. Large-amplitude magnetohydrodynamic activity with indications of RE loss is observed during the RE plateau when the edge safety factor decreases to less than 3, and the external kink mode is discussed to resolve this anomaly. Burst-like relaxations with small-amplitude magnetic fluctuations and ∼0.6 kHz frequency are confirmed from the spikes in the hard x-ray array signals under a negative loop voltage. Measurement of the RE energy distribution suggests that the instability is driven by medium-energy REs.

A study of the heating and current drive options and confinement requirements to access steady-state plasmas at Q ∼ 5 in ITER and associated operational scenario development

Access to steady-state (SS) plasma scenarios that can be potentially achieved in ITER by the exploitation of the neutral beam (NB) and electron cyclotron (EC) heating and current drive capabilities, including their foreseen upgrades, has been assessed and development of the Q ∼ 5 ITER SS operation (SSO) scenario has been carried out by combining all the necessary physics and engineering components. A set of modelling codes including 0.5D/1.5D transport and source modelling suites (METIS, ASTRA and CORSICA) and ideal MHD stability analysis codes (KINX and MISHKA) are applied to combined analysis and scenario development. Operating the plasma with a moderate density peaking factor (n e0/<n e> ∼ 1.3) for sufficient fusion gain (Q up to 5) at a low density (f GW = 0.6–0.8) and the required current drive efficiency produced an internal inductance (l i(3) ∼ 0.8–0 9) which improves the stability margin for low-n external ideal MHD modes. Based on this first observation, a combined operational space and ideal MHD stability analysis has recently identified Q ∼ 5 ITER SS target plasmas (Polevoi et al 2020 Nucl. Fusion 60 096024), and then the CORSICA scenario modelling suite has been applied to study access to the target plasmas as well as to develop a candidate operation scenario. Ideal MHD stability analysis on the SS plasmas has been performed using DCON embedded in the CORSICA scenario modelling suite. The use of off-axis electron cyclotron current drive (ECCD) with a power level of 20–30 MW from the equatorial and upper launchers was essential for the tailoring of the current profile to maintain ideal MHD stability of SS plasmas in ITER. Upgrading the NBI power from the baseline 33 MW to 49.5 MW provided the necessary current drive capability to allow fully non-inductive Q ∼ 5 operation with an energy confinement enhancement requirement (H 98 ≲ 1.6) similar to that achieved in some experiments in present tokamaks (Petty et al 2020 62nd Annual Meeting of the APS Division of Plasma Physics, Virtual Meeting (USA, 9–13 November 2020); Snyder et al 2019 Nucl. Fusion 59 086017; Solomon et al 2013 Nucl. Fusion 53 093033). The CORSICA simulations of the access to the Q ∼ 5 ITER SS target plasmas show that, provided that the enhancement of the energy confinement (H 98 ∼ 1.5–1.6) is achieved, it is possible for ITER to demonstrate the Q ∼ 5 SSO with NB and EC heating and current drive within the limits of the ITER Central Solenoid (CS)/Poloidal Field (PF) coil systems.

Hearing and reading: responding to the Articles of Perth in the 1618 court sermons of Lancelot Andrewes and John Buckeridge

ABSTRACT Although we often study the printed text of sermons, most originated as oral performances. Because the apparatus of printed versions tends to amplify the political and polemical aspects of a sermon, this focus has led some scholars to read sermons as they would polemical tracts, while ignoring an important purpose of the genre—the spiritual edification of hearers. This essay considers both oral and printed rhetorical effects in an examination of three English court sermons, all published in 1618. The study reveals that the oral rhetoric of the sermon speaks to an immediate need for individuals to reform their worship practices by incorporating both internal and external modes of piety into personal worship. The polemical and political attitudes, by contrast, would have been muted and implicit to hearers. As a result, I argue, a disproportionate emphasis on the printed text has dulled our sensitivity to early Laudianism’s moderate appeals.

Effect of differentarterial occlusion pressure and intermittent mode on KAATSU-loaded deep-squat exercise on the characteristics of thigh muscle activation

Objective: To investigate the effect of different arterial occlusion pressure and intermittent time on KAATSU-loaded deep-squat exercise on the characteristics of thigh muscle activation, find out the suitable relative value of personal blood pressure limit causing the maximum activation, and to provide some theoretical basis and practical reference for athletes to carry on the KAATSU Training scientifically. Methods: Ten elite male players were recruited, four kinds of external pressure condition with 0% arterial occlusion pressure (AOP), 40%AOP, 50%AOP, 60%AOP, respectively, were performed with 30%1RM(One repetition maximum)intensity of intermittent and continuous KAASTU-loaded deep-squat exercise. Wave plus wireless surface electromyography instrument was used to collect the surface EMG signals of the lower thigh muscle group. Root mean square (RMS) calculation was used to estimate muscle activity level. The normalized RMS values of the anterior thigh group and posterior thigh group were calculated by RMS of MVC, two-factor ANOVA analysis of variance were used to explore the effect of the activation of various muscle on external express and intermittent mode, to analyze the discrepancy during different external pressure. Results: ①A two-factor analysis of variance showed that different %AOP had significant effect on the normalized values of RMS of muscle measured by KAATSU deep-squat exercise(P＜0.05), but intermittent mode had no significant effect on the standard value of RMS of muscle(P＞0.05). The interaction of external pressure and intermittent mode on muscle RMS was not significant(P＞0.05); ②The normalized RMS values of Rectus Femoris, Vastus Medialis, Vastus Lateralis, Biceps Femoris, Semitendinosus were significantly increased (P＜0.05)in 50% AOP pressure condition during intermittent and continuous exercise; ③ The normalized RMS values of RF and VL were significantly increased(P＜0.05)in 50% AOP pressure condition during intermittent and continuous exercise. The %MVC values of Vastus Medialis and Semitendinosus were significantly increased(P＜0.05)in 60% AOP pressure condition during intermittent exercise. Conclusion: This study further verified that 50% AOP pressure can significantly improve the optimal activation quadriceps and posterior thigh groups and produce the best training effect for the high level handball players. It can not only promote the coordinated development of the agonist and antagonist, but also avoid overloading and prevent hamstring injury. At the same time, the intermittent mode is recommended to adopt the decompression intermittent mode.

Steady-state harmonic resonance of periodic interfacial waves with free-surface boundary conditions based on the homotopy analysis method

Abstract

Biosupercapacitor with an enzymatic cascade at the anode working in a sucrose solution

In this report, we demonstrate the advantages of the dual-mode operation of an enzymatic biosupercapacitor with nanostructured polypyrrole/nanocellulose, gold nanoparticle-based paper electrodes, sucrose as the anode fuel and molecular oxygen as the oxidant. The device allowed conversion of the sucrose biofuel, and offered storage of the generated power in the same, small-scale device. The external and internal biosupercapacitor re-charging modes were compared. The specific capacitance of the device was 1.8 F cm−2 at a discharge current density of 1 mA cm−2. The cell used in the charge/discharge mode of operation allowed retention of 49% of the initial capacitance after eight days of exhaustive discharging under external load. The discontinuous capacitive mode, preserved the biocatalysts activity for much longer time. The use of such enzyme-based electrical energy sources in the capacitive mode i.e. under discontinuous charging was demonstrated as a solution for preserving high specific capacitance and long-term operational stability.

Microfluidic fabrication of ZrO2 microspheres using improved external gelation aided by polyacrylamide networks

Microfluidic generation of emulsion microdroplets, combined with external gelation, is a promising method for the continuous production of high-quality ceramic microspheres. However, the external gelation mode is sensitive to the environmental concentration of sol-gel triggering agent, resulting in gel deformation due to uneven infiltration and reaction within the sol microdroplets. In this work, a polyacrylamide (PAM) gel network was used to prevent the microdroplets from undergoing apparent deformation throughout the gelation process, and dense ZrO2 microspheres with high monodispersity and sphericity were fabricated successfully. Importantly, owing to the assistance of PAM network, the external gelation process becomes less sensitive and can be treated with a substantially higher triggering agent concentration, thus allowing a faster and more efficient sol-gel production of ZrO2 ceramic microspheres.

Feedback-induced locking in semiconductor lasers with strong amplitude-phase coupling

The influence of optical feedback on semiconductor lasers has been a widely studied field of research due to fundamental interests as well as the optimization of optical data transmission and computing. Recent publications have shown that it is possible to induce a periodic pulsed like output in quantum-dot and quantum-well laser diodes utilizing the locking of the external cavity modes and the relaxation oscillation frequency. We present an in-depth analysis of this effect. We choose submonolayer quantum dots as a gain system, as these provide a relatively strong amplitude-phase coupling, which has proven to be very beneficial for these locking effects to occur. Introducing a new theoretical model we can correctly reproduce the essential features of the gain system and validate them by comparison to our experimental results. From this starting point we can further explore how the staircase behavior of the oscillation frequency with increasing pump current can be influenced by changing various laser parameters. The staircase behavior is induced by a reordering of the Hopf bifurcations giving birth to the regular pulsed-like oscillations.

Mechanical Behavior and Structure Optimization of Compressed PHP Packer Rubber

One of the core tools of horizontal well-staged fracturing completion technology is the compressed packer. The sealing and stability of packer rubber are key factors affecting the safe exploitation of high temperature, high pressure, and deep, complex oil and gas resources. The phenomenon of low setting pressure and early setting failure frequently occurs due to the unreasonable sealing structure. Therefore, in this paper, the tensile test of dumbbell hydrogenated nitrile butadiene rubber (HNBR) samples is conducted, and the stress-strain data of HNBR were obtained. The finite element mechanical model (FEM) of compressed PHP packer is established with consideration of material nonlinearity, geometric nonlinearity and double contact nonlinearity by adopting large-scale finite element analysis software ANSYS Workbench, verified by measured test data. Based on the verified FEM, the mechanical behavior and sealing performance of the original rubber under different setting loads are simulated. The contact pressure and its distribution, deformation, compression stroke of rubber and the relationship between them and axial loads are obtained. The mechanical behavior and sealing performance of packer rubber under different heights, thicknesses, external bevel angles, loading modes and steel-rubber friction coefficients with and without outburst prevention devices are investigated systematically using a manual-graphical optimization trial method. Results show that the packer rubber with the height of 75 mm, external bevel angle of 45°, steel-rubber friction coefficient ranging from 0.10 to 0.15 and outburst prevention devices can achieve the largest contact pressure and best sealing performance by adopting the setting method of bidirectional loading.

Resistive contributions to the stability of DIII-D ITER baseline demonstration discharges

Measurements of the plasma response to applied n = 1 perturbations from DIII-D ITER baseline scenario (IBS) demonstration discharges exhibit increasing amplitude prior to disruption inducing mode locking events. Simulations reveal that changes in ideal and resistive stability impact the response in the DIII-D IBS regime, well below the pressure limit of the external kink mode. The dependencies of the response measurements on the plasma normalized internal inductance ℓi and beta βN are qualitatively consistent with ideal MHD, although in most cases the amplitude of the measurements exceeds predictions, indicating that the experimental discharges are less stable than expected. Resistive MHD simulations of the response show improved compatibility with the measurements, and the closest agreement is obtained by including the experimental plasma rotation in the simulations. Although the input neutral beam torque is near zero, the simulations show that the corresponding level of rotation can lead to nearly complete screening of the pitch-resonant field component at the q = 2 surface. However, the simulation results exhibit a significant weakening of this screening effect at the lowest rotation levels in the dataset, concurrent with predictions of elevated response amplitudes that are consistent with measurements. These comparisons with DIII-D data provide a qualitative validation of a linear, resistive MHD response model.

Learning Model Development of Memorizing The Qur'an Through Integration of Internal and External Representation

This research aims to create a learning model of memorization of the Qur'an based on the nature of the brain that tends to require relevance between the projection of information that occurred internally in the brain (internal representation) and externally presented information outside the brain (external representation). Integration of the two modes of representation was carried out through a developmental study by adopting Research and Development (R &amp;amp; D) from Borg and Gall as a reference for the development of conceptual frameworks and memory models of Y Wang as a reference framework of the development of operational stages. From the model development process, several components of the model implementation have successfully been developed. The model implementation was operationally integrated with internal and external representation modes such as Phase I: the formulation of indicators, Phase II diagnostic assessment dealing with prior al-Qur’an memorizing ability, Phase III Conditioning students, Phase IV Coding memorizing materials, and Phase V repetition and recalling memorizing outcomes.

Vibrational spectra of calcium vanadyl phosphate hydrate mineral (sincosite): Raman and infrared spectroscopy

AbstractThe nondestructive micro‐Raman technique and the infrared spectroscopy are used to investigate sincosite mineral. Sincosite [Ca (VO)2(PO4)2·4H2O] exhibits the characteristic vibrational modes of PO4 tetrahedra, V(O,H2O)6 octahedra, H2O groups, and further external modes. The PO4 Raman and infrared stretching and bending vibrations of sincosite occur between 1,200 and 900 cm−1 and between 600 and 400 cm−1, respectively. The VO bond in the V(O,H2O)6 octahedra shows the most characteristic intense Raman band that appears at 984 cm−1. On the other hand, the H2O stretching and bending modes appear above 3,000 cm−1 and between 1,700 and 1,500 cm−1, respectively. The lattice vibrations occur below 200 cm−1.

Theoretical study of the D^0 rightarrow K^- pi ^+ eta reaction

We develop a model to study the D^0 rightarrow K^- pi ^+ eta weak decay, starting with the color favored external emission and Cabibbo favored mode at the quark level. A less favored internal emission decay mode is also studied as a source of small corrections. Some pairs of quarks are allowed to hadronize producing two pseudoscalar mesons, which posteriorly are allowed to interact to finally provide the K^- pi ^+ eta state. The chiral unitary approach is used to take into account the final state interaction of pairs of mesons, which has as a consequence the production of the kappa (K^*_0(700)) and the a_0(980) resonances, well visible in the invariant mass distributions. We also introduce the bar{K}^{*0} eta production in a phenomenological way and show that the s-wave pseudoscalar interaction together with this vector excitation mode are sufficient to provide a fair reproduction of the experimental data. The model provides the relative weight of the a_0(980) to the kappa excitation, and their strength is clearly visible in the low energy part of the K pi spectrum.

Bistable perception alternates between internal and external modes of sensory processing

SummaryPerceptual history can exert pronounced effects on the contents of conscious experience: when confronted with completely ambiguous stimuli, perception does not waver at random between diverging stimulus interpretations but sticks with recent percepts for prolonged intervals. Here, we investigated the relevance of perceptual history in situations more similar to everyday experience, where sensory stimuli are usually not completely ambiguous. Using partially ambiguous visual stimuli, we found that the balance between past and present is not stable over time but slowly fluctuates between two opposing modes. For time periods of up to several minutes, perception was either largely determined by perceptual history or driven predominantly by disambiguating sensory evidence. Computational modeling suggested that the construction of unambiguous conscious experiences is modulated by slow fluctuations between internally and externally oriented modes of sensory processing.

Dynamic Robustness Analysis of a Two-Layer Rail Transit Network Model

Robustness is one of the most important performance criteria for any rail transit network (RTN), because it helps us enhance the efficiency of RTN. Several studies have addressed the issue of RTN robustness primarily from the perspectives of given rail network structures or static distributions of passenger flow. An open problem that remains in fully understanding RTN robustness is how to take the spatio-temporal characteristics of passenger travel into consideration, since the dynamic passenger flow in an RTN can readily trigger unexpected cascading failures. This paper addresses this problem as follows: (1) we propose a two-layer rail transit network (TL-RTN) model that captures the interactions between a rail network and its corresponding dynamic passenger flow network, and then (2) we conduct the cascading failure analysis of the TL-RTN model based on an extended coupled map lattice (CML). Specifically, our proposed model takes the strategy of passenger flow redistribution and the passenger flow capacity of each station into account to simulate the human mobility behaviors and to estimate the maximum passenger flow appeal in each station, respectively. Based on the smart card data of RTN passengers in Shanghai, our experiments show that the TL-RTN robustness is related to both external perturbations and failure modes. Moreover, during the peak hours on weekdays, due to the large passenger flow, a small perturbation will trigger a 20% cascading failure of a network. Having ranked the cascade size caused by the stations, we find that this phenomenon is determined by both the hub nodes and their neighbors.

Using Raman spectroscopy and structural properties in understanding the ferroelectric nature of the RbMgPO4 phase transitions

Rubidium magnesium monophosphate RbMgPO4 compound was synthesized using the solid− state method. XRPD analysis, at room temperature, confirmed that the sample exhibits an unusual three-fold Pna21 superstructure in the orthorhombic system. EDS analysis proved the absence of external elements. SEM micrograph showed a microrod-like structure of grains with a uniform distribution. This compound undergoes two phase transitions of a ferroelectric nature at T1 = 448/433 K and T2 = 466/458 K (Heating/Cooling) revealing a rich polymorphism in the solid-state. These phase transitions were investigated using Raman spectroscopy analysis. The first shows a moderate reconstructive character revealing the coexistence of order-disorder and displacive components, while the second appears as a displacive one. These transitions are originated from the rotation of both MgO4 and PO4 in an inverse direction and a change of Mg coordination, to reach a high symmetry. Based on the order-disorder model, the analysis of the wavenumber, intensity, and width allowed us to attain information and to determine the thermal coefficients and the activation energies in each region. The temperature dependence of Raman spectra showed that the most important changes were observed in the external modes. The estimated critical values of the exponents (δ1,δ2) and (ξ01, ξ02), deduced from the reduced intensity of the thermosensitive band, were determined.

375 The quality of intrapartum cardiotocography in preterm labor

Although monitoring of the fetal heart rate with cardiotocography is now also applied to fetuses of lower gestational ages, the value and the quality of fetal heart rate monitoring in preterm fetuses is unclear. The aim of this study is to determine the quality of the fetal heart rate recording during preterm labor below 28 weeks gestational age and contribute to the discussion if cardiotocography is of value for the extreme preterm fetus. From January 2010 to December 2019, data of 95 fetal heart rate recordings of singleton fetuses between 24 to 28 weeks gestational age were collected at the Amsterdam University Medical Center, location VUmc. Fetal heart rate tracings had a duration of at least 30 minutes. Data were obtained via external ultrasound mode. The quality of the fetal heart rate recordings was determined by the median signal loss and by the proportion of cases exceeding the threshold of 20% signal loss, based on the guidelines of the International Federation of Gynaecology and Obstetrics (FIGO) for adequate quality. Signal loss was analyzed with a computer program. Data of all recordings were divided in two groups according to gestation to determine a relationship between signal loss and the following variables: gestational age, maternal overweight and mode of delivery. Non-parametric tests and chi-square tests were used to determine statistical significance. During the first stage of labor, approximately one-third of the recordings exceeded the 20% FIGO-criterion for adequate signal quality. In the second stage of labor, this was nearly 75%. Similarly, the median signal loss was 13% during the first and 30% during the second stage of labor (p<0.01). Gestational age, mode of delivery and maternal overweight were not associated with fetal signal loss. Almost one-third (31%) of first stage the fetal heart rate recordings during extreme preterm labor was of inadequate quality. During the second stage of labor quality was even worse with percentages up to 75%. Fetal heartrate monitoring in the extreme preterm fetus is therefore controversial and should be used with caution.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Analysis and Modeling of Enterprise Competitive Intelligence Based on Social Media User Comments

AbstractUnder modern information conditions, competitive intelligence has an important strategic role for an enterprise to reduce market, financial and other risks. How to correctly evaluate the value of competitive intelligence and make the right decision for an enterprise directly determines the survival and development of an enterprise. By establishing a co-occurrence relationship between the two, the core themes of corporate microblog communication are discovered. Proceeding from the basic theory of the value of competitive intelligence, it is proposed that due to the connection of business departments within the enterprise system, the transfer value of competitive intelligence within the enterprise system is changed, and a mathematical analysis method is used to establish a value transfer analysis model. The value-added process of enterprise competitive intelligence and the internal and external operational processes of the enterprise are unified, and the internal and external competitive intelligence value-added operation modes of enterprises led by different strategies are studied. This provides a new and widely-referenced operational reference for different companies to effectively formulate and implement their competition and cooperation strategies through internal and external competitive intelligence operations.