bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient dynamical system resource management method in cloud computing
Authors: Wu Tianshu , Wang Shuai , Shi Xiaoyu
Published: November 2019

The resource management of virtualisation system is a core issue in the field of cloud computing. For achieving the goal of efficient manage system resource without performance loss in clouding environment, the authors propose an optimal load balancing controller to assign the resource to different virtual machines, which run on a single physical server. Here, the authors focus on dynamical web workloads that the system resource management problem can be formulated as a dynamical optimisation problem. In the face of dynamical and robust workloads, the authors present an alternative approach based on the constrained boundary linear quadratic control (cBLQC) method, the optimal resource allocation scheme is solved by minimising the quadratic cost function with constrains on the system input and output. Different with existing works that assume a particular distribution for system noise or ignore the noise directly, the authors loosen the restrictions on system noise, which simply assume that system noise belongs with some reasonable norm‐bounded set. Experiments on the Xen‐based platform with a set of workload patterns show that the efficiency of authors’ method in terms of control precision and stability.
Research on feature point matching algorithm improvement using depth prediction
Authors: Chen Yongbin , Wang Guitang , Wu Liming
Published: November 2019

Feature point matching plays an important role in feature‐based image registration such as the scale‐invariant feature transform algorithm. Feature‐based image registration is widely used in visual simultaneous localisation and mapping, augmented reality, self‐driving etc. The most meaningful study on feature matching is to improve the accuracy and efficiency and this study pays attention to improving the accuracy by removing the mismatching feature points. Since most of the existed feature‐based image registration algorithms are not so strong and efficient enough in mismatch removing, in this study, the authors propose a novel mismatch removal algorithm by incorporating depth prediction into feature matching to improve the performance. In this approach, the depth maps are predicted in pixel‐wise through the given red–green–blue images using a deep learning algorithm. Experimental results show that their method outperforms conventional ones in mismatch removing.
Monte Carlo simulation of HPGe gamma‐spectrometry systems
Authors: Hou Dongjie , Guo Siming , Huang Jianwei , Wu Chong , Wu Jinjie
Published: November 2019

In order to obtain the relationship between energy and channel, the suitable radionuclides are chosen to calibrate. The result shows a goodness of fitting. The Monte Carlo simulation about the detection efficiency of the high purity germanium (HPGe) gamma‐spectrometry system was performed. The distance between radioactive source and the end cap is set 15, 20, 25 and 50 cm, respectively. The maximum absolute efficiency locates at around 80 keV. It can be concluded that the absolute efficiency is declining accompany with the increasing of distance. In the end, at the distance of 25 cm, the authors changed thickness of the dead layer and the source distribution to calculate. The maximum absolute efficiency is 8.56E−03, and the relative deviation is 0.0011. Then it was compared with the experimental result provided with the manufacturer. The result of simulation shows a certain agreement with the experimental results. This work will be helpful for calculating the efficiency of HPGe gamma‐spectrometry.
Fault localization on transformer winding by frequency response analysis and evidential reasoning
Authors: Duan Jiajun , He Yigang , Wu Wenjie
Published: November 2019

In this paper, a novel fault localization method combining frequency response analysis (FRA) and evidential reasoning process is proposed. FRA test is conducted at first so that we can obtain corresponding responses of several monitoring nodes on the winding. Traditional FRA interpretation methods simply compares those response curves, while in our work, evidential reasoning method is adopted to present beliefs about the fault locations. Extracted features from monitoring sensors are mapped into deviation matrix by which possibility assignments of each fault location is computed. So we finally obtain fault distribution probabilities. According to test calculation results, proposed method can give fault probabilities of each section of transformer winding, which correctly indicate the fault position.
Detect concrete cracks based on OTSU algorithm with differential image
Authors: Chen Bo , Zhang Xuan , Wang Ruitao , Li Zhen , Deng Wei
Published: November 2019

Aiming at the detection of concrete surface cracks, based on digital image processing technology, OTSU algorithm is processed based on differential image. First, the Gaussian filter is acted on the original image to obtain the smoothed image. Then the smoothed image is subtracted by the original image, the differential image is obtained. According to the OTSU algorithm, the optimal threshold on the differential image was calculated. As the characteristic cracks are a few pixels and with lower grey values, the pixels whose grey values are less than the mean value of the whole image to get the best threshold value were only calculated. Finally, remove the background noise based on the morphologic noise reduction to obtain the binary image of the crack. The experimental results show that the cracks can be discerned in complex backgrounds.
Paralleling voltage oscillation forecast method of energy device based on hysteresis curve equation
Authors: Xu You , Li Jiehao , Gao Qun , Yu Limin , Xu Wei , Li Feng
Published: November 2019

Power battery is widely used in backup power and new energy vehicles. Many countries have paid more and more attention to the safety of power battery. At present, the battery combination mode of series connection to parallel connection is conducive to the fast combination and unloading of high voltage system energy. It is an effective way for modular design and production of the power battery system. However, the voltage oscillation may appear when the voltage difference exists between the parallel modules. The phenomenon may affect the performance and safety of electric power and electric equipment. The voltage oscillation standard deviations in paralleling with different voltages were analysed, the voltage oscillation distribution map can be drawn. The reasonable parallel voltage range can be obtained by hysteresis curves, which were used to predict the limit of paralleling voltage. Lithium‐ion+ battery experiment was carried out and the result shows that the proposed method can predict the large voltage oscillation in battery paralleling, it can ensure the safety of battery module and it provided an effective forecast in paralleling for the new energy power electric system.
Design of a beam‐steering test bench based on OpenVPX architecture
Authors: Li Yanhua , Xiao Wenguang
Published: November 2019

Due to a large number of beam‐steering units and complex interfaces of a spaceborne phased‐array radar, the fault location in joint tests is difficult, the troubleshooting efficiency is low, and the progress of the project is difficult to guarantee. To solve the above problems, this study presents a design scheme of full‐array beam‐steering test bench based on OpenVPX architecture. This solution utilises OpenVPX architecture's advantages of good versatility, strong scalability, high transmission bandwidth, and rich I/O ports. It adopts commercial off‐the‐shelf modules that conform to the OpenVPX standard to build the hardware system. The serial rapid I/O switching technology is used to implement high‐speed interconnections and full‐function automated testing from the primary beam‐steering unit to the secondary beam‐steering units. Compared with the existing test methods, this test bench meets the development trend of commercialisation, interchangeability, interoperability and adoption of open industry standards for user testing requirements, which greatly improves the efficiency of full‐array beam‐steering testing and reducing labour intensity. The average test period is reduced from more than one week to less than one day, achieving the design requirements for rapid test and accurate fault location.
Research on fibre Bragg grating monitoring in the gravel soil landslide experiment
Authors: Gao Lei , Wang Yuan , Sun Yangyang , Zhang Qinghua , Zhang Zhenglin , Zeng Peng
Published: November 2019

Fibre Bragg Grating (FBG) sensor is a new sensor with numerous advantages. How to apply in the safety monitoring of landslide engineering is still in experiment and research stage. Here, FBG is used to monitor the landslide process of the gravel soil pile. Before monitoring experiment, the article first tests FBG packaging and burying effect by two tests in lab, one is sand pile landslide test which proves vertical buried is feasible and the other is loading test on the steel bar sensor which proves the wavelength change of FBG on steel bar sensor has a good linear relationship with the loading change. Then, buried the steel bar sensor in the gravel soil slope after simple encapsulation. Stress and strain monitoring results of grating sensors are obtained in landslide which is formed through the simulation of excavation construction. The experimental data show that through correct embedding FBG sensors can effectively monitor the stress–strain change of the slope. FBG provides a new way for the landslide early warning.
Fingerprinting the effects of hyperfine structure on CH and OH far infrared spectra using Wiener filter deconvolution
Authors: Jacob Arshia M. , Menten Karl M. , Wiesemeyer Helmut , Lee Min-Young , Güsten Rolf , Durán Carlos A.
Published: November 2019

Context. Despite being a commonly observed feature, the modification of the velocity structure in spectral line profiles by hyperfine structure complicates the interpretation of spectroscopic data. This is particularly true for observations of simple molecules such as CH and OH toward the inner Galaxy, which show a great deal of velocity crowding.

Aims. In this paper, we investigate the influence of hyperfine splitting on complex spectral lines, with the aim of evaluating canonical abundances by decomposing their dependence on hyperfine structures. This is achieved from first principles through deconvolution.

Methods. We present high spectral resolution observations of the rotational ground state transitions of CH near 2 THz seen in absorption toward the strong FIR-continuum sources AGAL010.62 − 00.384, AGAL034.258+00.154, AGAL327.293 − 00.579, AGAL330.954 − 00.182, AGAL332.826 − 00.549, AGAL351.581 − 00.352 and SgrB2(M). These were observed with the GREAT instrument on board SOFIA. The observed line profiles of CH were deconvolved from the imprint left by the lines’ hyperfine structures using the Wiener filter deconvolution, an optimised kernel acting on direct deconvolution.

Results. The quantitative analysis of the deconvolved spectra first entails the computation of CH column densities. Reliable N(CH) values are of importance owing to the status of CH as a powerful tracer for H2 in the diffuse regions of the interstellar medium. The N(OH)/N(CH) column density ratio is found to vary within an order of magnitude with values ranging from one to 10, for the individual sources that are located outside the Galactic centre. Using CH as a surrogate for H2, we determined the abundance of the OH molecule to be X(OH) = 1.09 × 10−7 with respect to H2. The radial distribution of CH column densities along the sightlines probed in this study, excluding SgrB2(M), showcase a dual peaked distribution peaking between 5 and 7 kpc. The similarity between the correspondingly derived column density profile of H2 with that of the CO-dark H2 gas traced by the cold neutral medium component of [CII] 158 μm emission across the Galactic plane, further emphasises the use of CH as a tracer for H2.
Different responses of primary producers to mild winter in macrophyte- and phytoplankton-dominated lakes
Authors: Lenard Tomasz , Ejankowski Wojciech , Poniewozik Małgorzata
Published: November 2019

Early ice-out on lakes or the absence of ice cover can lead to intense water mixing, high turbidity, and changes in nutrient balance and light conditions in the water, which in turn affect the phytoplankton community and submerged aquatic vegetation (SAV) in the aquatic environment. This study aimed to evaluate whether the effects of a mild winter on these primary producers are differentiated in two types of eutrophic lakes: phytoplankton-dominated (PDL), with a low proportion of SAV, and macrophyte-dominated (MDL), with extensive benthic vegetation. The physical and chemical parameters of the water, concentration of chlorophylla, and the biomass of phytoplankton and SAV were investigated in four small eutrophic lakes (Eastern Poland) during the growing season after cold winters (CW) and mild winters (MW). In both types of lakes, the concentrations of soluble and total nitrogen were higher and the values of soluble and total phosphorus were lower after the MW than after the CW. The concentration of chlorophyllaand the phytoplankton biomass were always higher in the PDL than in the MDL, but the increase in both parameters in the vegetation season after the MW was statistically important only in the PDL. A poor underwater light climate was stressful for the SAV in the PDL, but not in the MDL. The MW had negative effects on phytoplankton diversity and the loss of light-demanding macrophytes. However, the biomass of primary producers in the MDL seems to be more resistant to climate warming, in comparison to the PDL.
Total hip arthroplasty in patients with chronic liver disease: A systematic review
Authors: Onochie Elliot , Kayani Babar , Dawson-Bowling Sebastian , Millington Steven , Achan Pramod , Hanna Sammy
Published: November 2019

Introduction: Chronic liver disease (CLD) is a significant and increasingly prevalent co-morbidity in patients undergoing total hip arthroplasty (THA). These patients may develop metabolic bone disease (MBD) and systemic dysfunction, which pose challenges to THA surgery. This systematic review of literature aims to examine clinical outcomes and complications in patients with CLD undergoing THA and provide evidence-based approaches as to the optimization of their perioperative care.

Methods: A Pubmed search was performed, identifying eight studies on 28 514 THAs for inclusion. Two additional studies reported on 44 patients undergoing THA post liver transplant. These were reviewed separately.

Results: Increased early perioperative complications are reported recurrently. Review of long-term complications demonstrates an increased postoperative infection rate of 0.5% (p < 0.001) and perioperative mortality of 4.1% (p < 0.001). The need for revision surgery is more frequent at 4% (p < 0.001). Aetiology of need for revision surgery included; periprosthestic infection (70%), aseptic loosening (13%), instability (13%), periprosthetic fracture (2%) and liner wear (2%). THA in patients with liver transplants seems to offer functional improvement; however, no studies have formally assessed functional outcomes in the patient with active CLD.

Discussion: A multidisciplinary perioperative approach is suggested in order to minimize increased complication risks. Specific measures include optimizing haemoglobin and taking measures to reduce infection. This review also highlights gaps in available literature and guides future research to appraise functional outcomes, further detail long-term failure reasons and study any differences in outcomes and complications based on the range of operative approaches and available implant choices.
Urethral Reconstruction in a Reference Center in Eastern Colombia
Authors: Tobar-Roa Verónica , Ortiz-Zableh Ana María , Mantilla-Rey Daniel José , Sarmiento-Sarmiento Guillermo
Published: November 2019

Introduction and Objectives Urethral stricture is a complex pathology of multiple etiologies, and of unknown incidence in our country. There are multiple options for the management of urethral stricture, from minimally invasive procedures, like urethral dilation or direct vision internal urethrotomy, to open surgical reconstruction using excision and primary anastomosis (EPA), or augmented urethroplasty with tissue graft.

The aim of the present study is to describe the characteristics of the patients managed with urethral reconstructive surgery in a reference center in eastern Colombia.

Methods Observational retrospective cohort study. Data was obtained from patients undergoing urethral reconstructive surgery at the institution from August 2013 to December 2017. All of the surgeries were performed by the same surgical team. The clinical and demographic variables were collected, and the validated urethral stricture surgery patient-reported outcome measure (USS-PROM) questionnaire was applied.

Results A total of 56 patients were included in the study, 26 patients (46.4%) underwent excision and primary anastomosis (EPA), and 30 (53.6%) underwent graft urethroplasty. The average age at the time of the intervention was 53.3 years old. The most frequent etiology was trauma, and the mean length of the stenosis was 1.7 cm for the EPA group, and 3 cm for the graft urethroplasty group (p = 0.009). A history of previous surgery was found in 66% of the patients, and radiotherapy in 2 patients.

The mean follow-up was of 14 months (range: 0–52 months), observing similar success rates for both techniques. Despite of the small sample size, when analyzing the Kaplan-Meier curves, we observed a tendency of a better response in the group without previous treatments and with stenosis with a length < 2 cm.

The rate of postoperative complications was of 23%, with no statistical difference between the 2 groups. The USS-PROM questionnaire was applied to 29 patients, finding that 27 out of 29 respondents were satisfied with the results of the procedure, and all of them would recommend it to another person.

Conclusions The results of our study show that urethral reconstruction surgery performed in an experienced center is associated with a good success rate, and that patients are satisfied with the result of the procedure.
Two-electrode-pair electrocardiogram with no common ground between two pairs
Authors: Hsieh Hsin-Yen , Luo Ching-Hsing , Ye Jhong-Wun , Tai Cheng-Chi
Published: November 2019

An electrocardiogram (ECG) records the electrical activity of the heart using two electrodes to detect electrophysiological signals from the organ and one reference electrode (typically attached to the right leg) as the reference potential. An inconvenience of the three electrodes is that the grounds of the amplifiers are interconnected all over the body. To address this inconvenience, this paper proposes a two-electrode ECG measurement method with common electrodes instead of the reference electrode of the right leg. The power supply and the ground of the amplifier supplying the two electrode pairs are not connected and independent. Pasted on the skin with the body as the reference potential, both electrodes detect electrophysiological signals, transmitting the signals through two isolation amplifiers to an instrumentation amplifier filter and generating ECG waveforms. Both previous-stage electrode amplifier circuits of the isolation amplifiers used their respective power supplies; their grounds were unconnected to those of the power supplies. Similarly, the next-stage electrode amplifiers used their respective power supplies, with their grounds unconnected to those of the power supplies. Experiments yielded ECG signal waveforms in Leads I to III, with that of Lead I most resembling the waveforms of conventional reference electrodes. This method can be used to develop wireless ECG devices and portable ECG devices that eliminate the need for wiring to facilitate ECG measurement.
Radiometry for the vertical electron cyclotron emission from the runaway electrons at the COMPASS tokamak
Authors: Farník M. , Urban J. , Zajac J. , Bogár O. , Varavin M. , Casolari A. , Čeřovský J. , Ficker O. , Mlynář J. , Macúšová E. , Weinzettl V. , Hron M.
Published: November 2019

Due to an increased interest in runaway electron (RE) phenomena in tokamak research, the need for diagnostics of runaway electron population in plasma has emerged. A novel diagnostic of the nonthermal electron cyclotron emission from runaway electrons can be utilized for this purpose. It was designed and installed at the COMPASS tokamak based on the available heterodyne radiometer. The vertical ECE (V-ECE) system uses a 16-channel heterodyne radiometer with a vertically placed E2-band horn antenna with a 76.5–90 GHz frequency range front-end. Simulations with the ray-tracing SPECE code have shown a measurement feasibility of the runaway electrons with energies up to 1 MeV. Due to a low optical depth of the plasma in COMPASS during RE discharges, reflected waves from the tokamak wall can be detected as well. First results show strong connection with other RE diagnostics at COMPASS. The V-ECE can obtain important information about RE population evolution and primary generation mechanism.
Spin magnetoacoustic wave
Authors: Iqbal Z. , Younas Mehak , Khan Imran A. , Murtaza G.
Published: November 2019

Spectra of magnetosonic waves are studied by taking account of spin-up and spin-down electrons as two different fluids. It is found that the electron spin effect modifies the dispersions of the perpendicular and obliquely propagating magnetosonic waves even without considering the magnetization current effect. It may be noted that previously the spin effect in these dispersions appeared only due to magnetization. Furthermore, the consideration of separate spin evolution gives rise to the existence of a new spin dependent mode, i.e., spin magnetoacoustic mode along with fast and slow magnetosonic modes. It is also noted that spin polarization reduces the wave frequency of spin magnetoacoustic waves and fast magnetosonic waves while the frequency of the slow mode was slightly affected by these effects. The relevance of the present investigation in the dense astrophysical environments is also pointed out.
Single-pass non-destructive electronic detection of charged particles
Authors: Kiffer Markus , Ringleb Stefan , Stallkamp Nils , Arndt Béla , Blinov Ilya , Kumar Sugam , Stahl Stefan , Stöhlker Thomas , Vogel Manuel
Published: November 2019

We have devised an experimental method and apparatus for the simultaneous nondestructive determination of the absolute ion number, ion kinetic energy, and length of bunches of charged particles. We have built and operated a corresponding electronic detector that is based on induced charges and their subsequent low-noise amplification at cryogenic temperatures. We have performed measurements with bunches of low-energy highly charged ions from an electron-beam ion source that show the capability of the methods and their implementation. We discuss requirements for, and applications of, such detectors with a particular view on the obtainable information and their sensitivity.
Theoretical estimation of tunnel currents in hetero-junctions: The special case of nitride tunnel junctions
Authors: Duboz Jean-Yves , Vinter Borge
Published: November 2019

In tunnel junctions, an electron current is transformed into a hole current via a quantum tunnel effect through the semiconductor bandgap. We derive a complete theory for the current through tunnel junctions based on Kane's approach and extended to the general case of a nonconstant electric field and arbitrary potentials in heterostructures. The theory mixes an analytical approach based on Fermi's golden rule and the numeric calculation of wave functions in the heterostructure. The parallel component of the transport is included in the calculation and the symmetry of the conduction and valence band states are taken into account in the transition rates. The calculation is limited to the elastic case and leads to a simple and fast estimation of the tunnel current in any semiconductor junction. We applied our calculation to III-nitrides due to the importance of tunnel junctions in these materials, since they allow circumventing the problem of insufficient p-type doping in GaN and AlGaN. Our approach is also particularly relevant in III-nitride heterojunctions owing to the large band offsets and varying piezoelectric fields present in these materials. The resulting dependence of the inverse current-voltage characteristics on several parameters is studied, making it possible to optimize thickness, doping, and composition of a smaller gap semiconductor layer inserted in the junction. Among all parameters, we show the importance of the doping levels in the n and p regions, while a thin undoped interlayer with a smaller bandgap energy critically enhances the tunnel transparency.
Temperature behavior of long-wave acoustic phonons in relaxor ferroelectric Na1/2Bi1/2TiO3
Authors: Derets Nikita K. , Fedoseev Alex I. , Syrnikov Pavel P. , Lushnikov Sergey G. , Kojima Seiji
Published: November 2019

This work presents the results of study of the behavior of longitudinal (LA), quasilongitudinal (QLA), and transverse (TA) acoustic phonons in single crystals of Na1/2Bi1/2TiO3 (NBT) within a temperature range from 110 K to 850 K. Measurements were carried out by means of Brillouin light scattering on phonons with a wave vector qph || [100], qph || [010], and qph || [110], regarding the cubic phase of NBT. Temperature dependences of sound velocity, attenuation, and intensity of LA, QLA, and TA phonons have been plotted. Anomalies in the behavior of sound velocity and attenuation of LA phonons in the vicinity of antiferrodistortive structural phase transition from the cubic to the tetragonal phases have been found. It is shown that broad anomalies in the sound velocity and attenuation of acoustic phonons typical to diffuse phase transition are not connected directly with the anomaly in the dielectric permittivity of the crystal. Elastic C11 and C44 modules in the cubic phase of NBT have been defined.
A three-dimensional model of spiral null pair to form ion-scale flux ropes in magnetic reconnection region observed by Cluster
Authors: Guo Ruilong , Pu Zuyin , Yao Zhonghua , Dunlop Malcolm , Bogdanova Yulia V. , Wei Yong , Wang Xiaogang , Xiao Chijie , He Jiansen , Fu Suiyan , Xie Lun , Fazakerley Andrew N. , Wan Weixing
Published: November 2019

The magnetic structure and topology of the three-dimensional magnetic reconnection region are significantly dynamic and complex. Small-scale flux ropes and magnetic null points are frequently detected in the reconnection outflow region and diffusion region due to the increased in situ measurements at high temporal cadences. Previous studies have demonstrated that X-line and small-scale flux ropes are both related to null points. In this study, by applying a fitting-reconstruction method with the input of the Cluster dataset, we reveal three types of spiral null pairs that serve as the skeleton of the flux ropes. Two spiral nulls can be connected by a spine, or by a separator, or by both a spine and a separator. A theoretical model is proposed to explain these spiral null pairs. The observational results and the model indicate that the number of magnetic loops of the flux rope is restricted by the linkage pattern of two nulls, while the flux rope is confined by the two nulls and their fan surfaces. The model predicts that the magnetic perturbations in the reconnection region can transform the linkage types of the nulls and eventually lead to the evolution of flux ropes.
On the mean field limit for Brownian particles with Coulomb interaction in 3D
Authors: Li Lei , Liu Jian-Guo , Yu Pu
Published: November 2019

In this paper, we consider the mean field limit of Brownian particles with Coulomb repulsion in 3D space using compactness. Using a symmetrization technique, we are able to control the singularity and prove that the limit measure almost surely is a weak solution to the limiting nonlinear Fokker-Planck equation. Moreover, by proving that the energy almost surely is bounded by the initial energy, we improve the regularity of the weak solutions. By a natural assumption, we also establish the weak-strong uniqueness principle, which is closely related to the propagation of chaos.
Penetration properties of resonant magnetic perturbation in EAST Tokamak
Authors: Zhang H. W. , Ma Z. W. , Zhang W. , Sun Y. W. , Yang X.
Published: November 2019

Our three-dimensional toroidal magnetohydrodynamics code [CLT (Ci-Liu-Ti, which means magnetohydrodynamics in Chinese)] is upgraded to CLTx in which the simulation domain extends to a scrape-off layer (SOL). Linear simulation results of resonant magnetic perturbation (RMP) for edge-localized-mode mitigation discharge 52340 in EAST Tokamak agree well with those from the MARS-F code. With the presence of the X-point and the SOL, the RMP amplitude and phase shift in the pedestal region, especially for a higher m mode, are largely affected by the resistivity in the SOL. A phase shift of π for resonant harmonics in vacuum and with a plasma response is observed, which is quite different from the π/2 shift due to the presence of screen current suggested in the previous studies. Simulation results with different resistivities suggest that the amplitude reduction and the phase shift of the resonant harmonics increase with decreasing the resistivity.
Systematic method to evaluate energy dissipation in adiabatic quantum-flux-parametron logic
Authors: Yamae Taiki , Takeuchi Naoki , Yoshikawa Nobuyuki
Published: November 2019

Adiabatic quantum-flux-parametron (AQFP) logic is an energy-efficient superconductor logic. It operates with zero static power dissipation and very low dynamic power dissipation owing to adiabatic switching. In previous numerical studies, we have evaluated the energy dissipation of basic AQFP logic gates and demonstrated sub-kBT switching energy, where kB is Boltzmann's constant and T is the temperature, by integrating the product of the excitation current and voltage associated with the gates over time. However, this method is not applicable to complex logic gates, especially those in which the number of inputs is different from the number of outputs. In this study, we establish a systematic method to evaluate the energy dissipation of general AQFP logic gates. In the proposed method, the energy dissipation is calculated by subtracting the energy dissipation of the peripheral circuits from that of the entire circuit. In this way, the energy change due to the interaction between gates, which makes it difficult to evaluate the energy dissipation, can be deducted. We evaluate the energy dissipation of a majority gate using this method.
The evolution of rogue wave triplets and super rogue waves in superthermal polarized space dusty plasma
Authors: Singh Kuldeep , Saini N. S.
Published: November 2019

This present investigation has been instigated to examine the impact of polarization force on modulational instability of dust acoustic (DA) waves and transition of rogue wave triplets to super rogue waves in dusty plasma composed of negative dust as fluid, Boltzmannian electrons, and superthermal ions. The presence of superthermal ions has remarkably altered the impact of polarization force. An increment in ion superthermality index restricts the polarization parameter toward smaller values. By adopting the reductive perturbation technique, the nonlinear Schrödinger equation (NLSE) is procured that determines the modulational instability of the dust acoustic waves. It is observed that the effect of polarization force is constricted by the wavenumber domain in the advent of the instability region. The rational solution of NLSE describes the evolution of dust acoustic rogue wave triplets, which further transform into the super rogue waves by means of superposition of triplets. It is remarked that the amalgamation of polarization force and superthermal ions have an explicit impact on the characteristics of different kinds of dust acoustic rogue waves. It is intensified that our present theoretical pronouncements may shed light on the salient features of different kinds of DA rogue waves in laboratory experiments and space/astrophysical regions, especially in Saturn's magnetosphere, planetary rings, and comet tails, etc.
Numerical analysis for optimization of the sidewall conditions in a capacitively coupled plasma deposition reactor
Authors: Kim Ho Jun , Kim Jin Seok , Lee Hae June
Published: November 2019

Capacitively coupled plasma (CCP) is mainly being used in the semiconductor industry for plasma-enhanced chemical vapor deposition of uniform thin films. Because a discharge volume in the standard configuration of a CCP reactor is surrounded not only with electrode surfaces but also with a sidewall, the sidewall conditions affect the deposition rate profiles noticeably. By toggling the boundary condition from a grounded conductor to dielectrics with the variations of the relative permittivity and the thickness, we compare the spatial profiles for the species densities, ionization rate, power absorption, and particle fluxes in a SiH4/He CCP. Through the SiH4/He CCP fluid model, it is found that a thick and low-permittivity insulator achieves the most uniform plasma density distribution in the interelectrode region and, consequently, the best uniformity in the deposition rate profile of an a-Si:H film. As a validation, experimental results are compared with fluid modeling results, and they match well. For additional validation, a particle-in-cell simulation of pure Ar discharge is also performed. Although simulation conditions are totally different from those of the SiH4/He fluid model, it consistently demonstrates that the dielectric sidewall brings about more uniform distributions of the plasma parameters than the grounded sidewall.
Abnormal dependence of multiferroicity on high-temperature electro-poling in GdMn2O5
Authors: Zheng S. H. , Gong J. J. , Li Y. Q. , Li C. F. , Tang Y. S. , Zhang J. H. , Lin L. , Yan Z. B. , Jiang X. P. , Cheong S. W. , Liu J.-M.
Published: November 2019

Magnetically induced ferroelectric polarization in rare-earth RMn2O5 manganites is believed to originate from the symmetric exchange striction associated with a specific antiferromagnetic phase in the low temperature (T) region and would be irrelevant with electropoling in the high-T paramagnetic-paraelectric phase region. In this work, we demonstrate that low-T pyroelectric polarization of GdMn2O5 single crystals along the b axis in the antiferromagnetic phase exhibits remarkable dependence on the electropoling history imposed in the high-T paramagnetic-paraelectric phase. In particular, the high-T electropoling results in a reversal of ferroelectric polarization in the low-T region, which can be flopped back by the electropoling being sustained in the low-T ferroelectric region. The existence of an electrically polarizable magnetic cluster state in the high-T paramagnetic-paraelectric region is proposed based on a combination of experimental observations and first-principles calculations. An intrinsic correlation between the low-T antiferromagnetic ordering and the high-T polarizable state is discussed. The present experiments unveil the emergent phenomena on multiferroicity of RMn2O5 and suggest an alternative scenario for electrocontrol of magnetism.
Effect of quantum charge screening on dual plasmon scattering
Authors: Akbari-Moghanjoughi M.
Published: November 2019

In this paper, we investigate the resonant scattering of driven linear oscillations in an isothermal electron gas with an arbitrary degree of degeneracy. The coupled pseudoforce system is obtained from the quantum hydrodynamic model and is extended to include the driving pseudoforce and pseudodamping effect in order to study the quantum charge shielding on the resonant scattering, heat capacity, and Friedel oscillations around an impurity charge. It is shown that the resonant scattering phenomenon takes place when the driver wavelength matches either scale lengths of plasmon excitations, which arise due to single electron oscillations and collective electron plasma excitations. It is remarked that in the presence of a periodic density structure such as in metals, plasmon interactions with a periodic lattice structure can lead to resonant Bragg-like scattering. A generalized energy dispersion relation for pseudodamped plasmon excitations is obtained, which indicates a critical screening point beyond which the plasmon excitations behave only particlelike. It is shown that the heat capacity of plasmon excitations and the static quantum charge screening are strongly affected by interaction between the plasmon and the charge screening scale lengths.
Ferroelectric barium titanate derivatives containing Mo and Mg for transparent photovoltaic applications
Authors: Shafir Or , Yang Jing , Rappe Andrew M. , Grinberg Ilya
Published: November 2019

Using first-principles methods, we investigate the electronic properties of the [Ba(Mo1/2,Mg1/2)O3]x-[BaTiO3]1−x solid solution derived from barium titanate as a potential candidate to be used in photovoltaic devices. Focusing on the bandgap and its origin, we study the effect of different possible Mo and Mg contents, arrangements, and phases of [Ba(Mo1/2,Mg1/2)O3]x-[BaTiO3]1−x. We find that [Ba(Mo1/2,Mg1/2)O3]0.25-[BaTiO3]0.75 is a viable candidate for use in transparent photovoltaics due to its energy bandgap of 2.6 eV in the rhombohedral phase. In all cases, [Ba(Mo1/2,Mg1/2)O3]x-[BaTiO3]1−x materials exhibit spontaneous polarization that allows the exploitation of the bulk photovoltaic effect and in principle may allow high power conversion efficiency exceeding the Shockley-Queisser limit for these materials.
Josephson penetration depth in coplanar junctions based on 2D materials
Authors: Li Tianyi , Gallop John C. , Hao Ling , Romans Edward J.
Published: November 2019

Josephson junctions and superconducting quantum interference devices with graphene or other 2D materials as the weak link between superconductors have become a hot topic of research in recent years, with respect to both fundamental physics and potential applications. We have previously reported ultrawide Josephson junctions (up to 80 μm wide) based on chemical-vapor-deposition graphene where the critical current was found to be uniformly distributed in the direction perpendicular to the current. In this paper, we demonstrate that the unusually large Josephson penetration depth λJ that this corresponds to is enabled by the unique geometric structure of Josephson junctions based on 2D materials. We derive a new expression for the Josephson penetration depth of such junctions and verify our assumptions by numerical simulations.
Dust-ion-acoustic modes at comet 67P/Churyumov-Gerasimenko
Authors: Chen Hui , Yang Weiheng , Liu Sanqiu
Published: November 2019

The dynamics of dust-ion-acoustic (DIA) modes at Comet 67P/Churyumov-Gerasimenko, where H2O+ ions with warm and cold electrons as well as dust grains were detected, are investigated within the two-electron-temperature dusty plasmas model by the kinetic theory. In terms of current-driven DIA waves, the bulk electron drift is assumed to overcome Landau damping due to resonance interaction of DIA waves with cometary ions. The results show that the presence of charged dust grains lowers the critical drift velocity of bulk electrons and the Landau damping rates, and inversely enhances the growth rates of DIA instabilities. Consequently, the presented dust grains make the DIA modes more easily excited. The present results indicate that the DIA wave may be a possible candidate to interpret the wave observation of the European Space Agency's spacecraft “Rosetta” at comet 67P/Churyumov-Gerasimenko.
Anisotropic diffusion of 2D superparamagnetic dusty plasma liquids
Authors: Yang F. , Liu S. F. , Kong W. , Li Yunlong
Published: November 2019

Diffusion of two-dimensional (2D) superparamagnetic dust grains interacting via both Yukawa and magnetic dipole-dipole interactions is investigated based on the Langevin dynamics simulation. The magnetic dipole moment, induced by the external magnetic field, is tilted at angle α relative to the 2D layer. It is demonstrated that the system in the liquidlike state behaves in anisotropic diffusion when α is larger than the agglomeration threshold, and the anisotropic diffusions are identified as the normal type. The anisotropy degree depends on the strength of magnetic dipole-dipole interaction and tilt angle of the magnetic dipole moment. An empirical law describing the anisotropy degree as a function of α is given.
Primary amines enhance triplet energy transfer from both the band edge and trap state from CdSe nanocrystals
Authors: Rigsby Emily M. , Lee Kevin , Sun Jefferson , Fishman Dmitry A. , Tang Ming L.
Published: November 2019

In this study, the role that primary amines play during triplet energy transfer from photoexcited CdSe nanocrystals (NCs) was examined. Colloidally synthesized CdSe NCs were placed in varying concentrations of 1-propyl- or 1-octylamine, with and without 2-anthracenecarboxylic acid transmitter ligands attached. This primary amine increases upconversion quantum yield approximately 5-fold. Further addition of amine does not improve photon upconversion, as CdSe NC photoluminescence (PL) increases at the expense of triplet energy transfer. Transient absorption measurements show that the amine plays three key roles. Primary amines enhance NC PL by decreasing the nonradiative decay rate, increase the rate of triplet energy transfer, and enable the broad trap state in these CdSe NCs to participate in triplet photosensitization.
Landscape and flux govern cellular mode-hopping between oscillations
Authors: Li Chunhe , Ye Leijun
Published: November 2019

Recently, a “mode-hopping” phenomenon has been observed in a NF-κB gene regulatory network with oscillatory tumor necrosis factor (TNF) inputs. It was suggested that noise facilitates the switch between different oscillation modes. However, the underlying mechanism of this noise-induced “cellular mode-hopping” behavior remains elusive. We employed a landscape and flux approach to study the stochastic dynamics and global stability of the NF-κB regulatory system. We used a truncated moment equation approach to calculate the probability distribution and potential landscape for gene regulatory systems. The potential landscape of the NF-κB system exhibits a “double ring valley” shape. Barrier heights from landscape topography provide quantitative measures of the global stability and transition feasibility of the double oscillation system. We found that the landscape and flux jointly govern the dynamical “mode-hopping” behavior of the NF-κB regulatory system. The landscape attracts the system into a “double ring valley,” and the flux drives the system to move cyclically. As the external noise increases, relevant barrier heights decrease, and the flux increases. As the amplitude of the TNF input increases, the flux contribution, from the total driving force, increases and the system behavior changes from one to two cycles and ultimately to chaotic dynamics. Therefore, the probabilistic flux may provide an origin of chaotic behavior. We found that the height of the peak of the power spectrum of autocorrelation functions and phase coherence is correlated with barrier heights of the landscape and provides quantitative measures of global stability of the system under intrinsic fluctuations.
Vegetation pattern formation: The mechanisms behind the forms
Authors: Meron Ehud
Published: November 2019

A simple principle relating growth to lateral water transport explains the variety of self-organized vegetation patchiness.
The new science of novae
Authors: Mukai Koji , Sokoloski Jennifer L.
Published: November 2019

The discovery of γ-ray emission from novae has been used not only to better understand sudden brightening events but also to answer some old questions and raise new ones.
Fluid dynamics of wildfires
Authors: Linn Rodman
Published: November 2019

Once a wildfire is ignited, complex interactions with the local winds affect how it behaves.
Comprehensive mapping of abiotic stress inputs into the soybean circadian clock
Authors: Li Meina , Cao Lijun , Mwimba Musoki , Zhou Yan , Li Ling , Zhou Mian , Schnable Patrick S. , O’Rourke Jamie A. , Dong Xinnian , Wang Wei
Published: November 2019

The plant circadian clock evolved to increase fitness by synchronizing physiological processes with environmental oscillations. Crop fitness was artificially selected through domestication and breeding, and the circadian clock was identified by both natural and artificial selections as a key to improved fitness. Despite progress inArabidopsis, our understanding of the crop circadian clock is still limited, impeding its rational improvement for enhanced fitness. To unveil the interactions between the crop circadian clock and various environmental cues, we comprehensively mapped abiotic stress inputs to the soybean circadian clock using a 2-module discovery pipeline. Using the “molecular timetable” method, we computationally surveyed publicly available abiotic stress-related soybean transcriptomes to identify stresses that have strong impacts on the global rhythm. These findings were then experimentally confirmed using a multiplexed RNA sequencing technology. Specific clock components modulated by each stress were further identified. This comprehensive mapping uncovered inputs to the plant circadian clock such as alkaline stress. Moreover, short-term iron deficiency targeted different clock components in soybean andArabidopsisand thus had opposite effects on the clocks of these 2 species. Comparing soybean varieties with different iron uptake efficiencies suggests that phase modulation might be a mechanism to alleviate iron deficiency symptoms in soybean. These unique responses in soybean demonstrate the need to directly study crop circadian clocks. Our discovery pipeline may serve as a broadly applicable tool to facilitate these explorations.
Effect of silage characteristics on enteric methane emission from ruminants.
Authors: Gastelen S. van , Bannink A. , Dijkstra J.
Published: November 2019

This review evaluates the effects of silage characteristics on enteric methane (CH
4
) emission from ruminants by performing a meta-analysis. A total of 17 studies were selected from the literature, and the relationship between CH
4
yield (g/kg dry matter [DM] intake) and silage characteristics was determined using a mixed model univariate regression procedure. For grass silage, organic matter digestibility (%;
R
2
=0.74) and crude protein content (g/kg DM;
R
2
=0.36) were negatively associated, and neutral detergent fibre (NDF) content (g/kg DM;
R
2
=0.44) was positively associated with CH
4
yield. This indicates that increased grass silage quality consistently decreases CH
4
yield and may be an effective enteric CH
4
mitigation strategy. Similarly, optimizing maize silage quality appears to be an effective enteric CH
4
mitigation strategy, because NDF content (g/kg DM;
R
2
=0.60) was positively associated with CH
4
yield. Upon replacing grass silage with maize silage, dietary starch content (g/kg DM;
R
2
=0.62) and silage replacement level (%;
R
2
=0.33) were negatively associated, and NDF content (g/kg DM;
R
2
=0.34) was positively associated with CH
4
yield. These results indicate that replacing grass silage with maize silage consistently decreases CH
4
yield and may be an effective enteric CH
4
mitigation strategy. In contrast, replacement of alfalfa silage with maize silage was not associated with CH
4
yield and does not appear to be an effective strategy to decrease CH
4
yield. In conclusion, management practices to improve silage quality are a potent mitigation strategy to reduce enteric CH
4
emission per unit of feed fed to ruminants, and implications of silage quality have to be addressed when assessing greenhouse gas emissions in ruminant production.