bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic and sensitive hybrid fs/ps vibrational CARS thermometry using a quasi-common-path second-harmonic bandwidth-compressed probe
Authors: Zhao Huijie , Tian Ziyang , Wu Tao , Li Yan , Wei Haoyun
Published: February 2021

We demonstrate a 1-kHz, single-shot, dynamic, and sensitive flame temperature measurement using hybrid femtosecond/picosecond vibrational coherent anti-Stokes Raman scattering. This benefits from a 7-cm−1, 240-μJ, and sideband-free picosecond pulse out of a broadband 35-fs pulse through a quasi-common-path second harmonic bandwidth compressor system. Measurements around optimal time delay exhibit superior performance with a temperature inaccuracy of less than 1% and a precision of ∼2% at 1790 K. These results demonstrate the advantages and potential for the accurate and fast temperature measurement in practical or harsh environments.
Analysis of input-induced oscillations using the isostable coordinate framework
Authors: Wilson Dan
Published: February 2021

Many reduced order modeling techniques for oscillatory dynamical systems are only applicable when the underlying system admits a stable periodic orbit in the absence of input. By contrast, very few reduction frameworks can be applied when the oscillations themselves are induced by coupling or other exogenous inputs. In this work, the behavior of such input-induced oscillations is considered. By leveraging the isostable coordinate framework, a high-accuracy reduced set of equations can be identified and used to predict coupling-induced bifurcations that precipitate stable oscillations. Subsequent analysis is performed to predict the steady state phase-locking relationships. Input-induced oscillations are considered for two classes of coupled dynamical systems. For the first, stable fixed points of systems with parameters near Hopf bifurcations are considered so that the salient dynamical features can be captured using an asymptotic expansion of the isostable coordinate dynamics. For the second, an adaptive phase-amplitude reduction framework is used to analyze input-induced oscillations that emerge in excitable systems. Examples with relevance to circadian and neural physiology are provided that highlight the utility of the proposed techniques.
The dynamics of parallel-plate and cone–plate flows
Authors: Oza Anand U. , Venerus David C.
Published: February 2021

Rotational rheometers are the most commonly used devices to investigate the rheological behavior of liquids in shear flows. These devices are used to measure rheological properties of both Newtonian and non-Newtonian, or complex, fluids. Two of the most widely used geometries are flow between parallel plates and flow between a cone and a plate. A time-dependent rotation of the plate or cone is often used to study the time-dependent response of the fluid. In practice, the time dependence of the flow field is ignored, that is, a steady-state velocity field is assumed to exist throughout the measurement. In this study, we examine the dynamics of the velocity field for parallel-plate and cone–plate flows of Newtonian fluids by finding analytical solutions of the Navier–Stokes equation in the creeping flow limit. The time-dependent solution for parallel-plate flow is relatively simple as it requires the velocity to have a linear dependence on radial position. Interestingly, the time-dependent solution for cone–plate flow does not allow the velocity to have a linear dependence on radial position, which it must have at the steady state. Here, we examine the time-dependent velocity fields for these two flows, and we present results showing the time dependence of the torque exerted on both the stationary and rotating fixtures. We also examine the time dependence of spatial non-homogeneities of the strain rate. Finally, we speculate on the possible implications of our results in the context of shear banding, which is often observed in parallel-plate and cone–plate flows of complex fluids.
Improving magnetic nanothermometry accuracy through mixing-frequency excitation
Authors: Guo Silin , Liu Jay , Du Zhongzhou , Liu Wenzhong
Published: February 2021

This study proposes a temperature model for the relaxation of magnetic nanoparticles and a phase measurement method under a mixing-frequency excitation field, which can improve the accuracy of temperature measurements in magnetic nanothermometry. According to the Debye-based magnetization model for magnetic nanoparticles, phases at mixing frequencies are used to solve the problem of a delay in the relaxation phase of the magnetic field at a high frequency. This method can improve the signal-to-noise ratio of the response of the magnetic nanoparticles and weaken the phase shift of the detection coils caused by the changes in temperature. The results of experiments show that the proposed method can achieve static temperature measurement error less than 0.1 K and dynamic temperature measurement error less than 0.2 K.
Bubbling transition as a mechanism of destruction of synchronous oscillations of identical microbubble contrast agents
Authors: Garashchuk Ivan R. , Sinelshchikov Dmitry I.
Published: February 2021

We study the process of the destruction of synchronous oscillations in a model of two interacting microbubble contrast agents exposed to an external ultrasound field. Completely synchronous oscillations in this model are possible in the case of identical bubbles when the governing system of equations possess a symmetry leading to the existence of a synchronization manifold. Such synchronous oscillations can be destructed without breaking the corresponding symmetry of the governing dynamical system. Here, we describe the phenomenological mechanism responsible for such destruction of synchronization and demonstrate its implementation in the studied model. We show that the appearance and expansion of transversally unstable areas in the synchronization manifold leads to the transformation of a synchronous chaotic attractor into a hyperchaotic one. We also demonstrate that this bifurcation sequence is stable with respect to symmetry breaking perturbations.
Analytic gradients for multiconfiguration pair-density functional theory with density fitting: Development and application to geometry optimization in the ground and excited states
Authors: Scott Thais R. , Oakley Meagan S. , Hermes Matthew R. , Sand Andrew M. , Lindh Roland , Truhlar Donald G. , Gagliardi Laura
Published: February 2021

Density fitting reduces the computational cost of both energy and gradient calculations by avoiding the computation and manipulation of four-index electron repulsion integrals. With this algorithm, one can efficiently optimize the geometries of large systems with an accurate multireference treatment. Here, we present the derivation of multiconfiguration pair-density functional theory for energies and analytic gradients with density fitting. Six systems are studied, and the results are compared to those obtained with no approximation to the electron repulsion integrals and to the results obtained by complete active space second-order perturbation theory. With the new approach, there is an increase in the speed of computation with a negligible loss in accuracy. Smaller grid sizes have also been used to reduce the computational cost of multiconfiguration pair-density functional theory with little effect on the optimized geometries and gradient values.
Smart power system of biocompatible and flexible micro-supercapacitor
Authors: Chen Caifeng , Wen Hao , Qu Zhenkui , Wang Hao , Liu Xiangyang
Published: February 2021

Flexible micro-supercapacitor (MSC) is an ideal energy storage device for flexible and small-scale electronics, specifically some human health sensors, because of its flexibility, long working life, high power density, and high charge and discharge rate. In this work, a smart power system of MSC is developed. First, utilizing ink-jet printing and electrochemical deposition, flexible MSC is fabricated on the biocompatible substrate of a modified silk protein film, making the power system suitable for implantable devices. Second, aiming at the common drawbacks of small energy density and large voltage variation of MSC, a wireless charging component and a wireless inductor–capacitor (LC) voltage sensor are integrated with the MSC unit. Using pulse charging mode, charging and voltage detection can be performed at the same time. The LC voltage sensor, using varactor diodes to realize voltage capacitance mapping, does not need extra ICs or consume any energy. Such a system has great application potential as the energy supply part of small devices implanted in the human body.
Effect of surface treatments on ALD Al2O3/4H-SiC metal–oxide–semiconductor field-effect transistors
Authors: Jayawardhena I. U. , Ramamurthy R. P. , Morisette D. , Ahyi A. C. , Thorpe R. , Kuroda M. A. , Feldman L. C. , Dhar S.
Published: February 2021

Silicon carbide (4H) based metal–oxide–semiconductor field-effect transistors provide capabilities in high power and high temperature inaccessible to silicon. However, the performance of thermally grown oxide-based devices remains limited by oxide/semiconductor interface defects. This research employs deposited dielectrics, Al2O3, rather than thermal oxidation. Investigation of various pre-deposition processes reveals different degrees of improvements in the electronic properties. An optimum structure employs the preparation of a nitrided surface via NO annealing, a process known to passivate surface defects, a hydrogen exposure, followed by Al2O3 deposition. Inversion layer field-effect mobilities as high as 52 cm2/V s are reported in the optimum structures. Capacitance–voltage measurements and field-effect mobility characteristics indicate a trapping limited conductivity in Al2O3/4H-SiC inversion channels similar to SiO2/4H-SiC. Leakage currents and interface breakdown are also reported for various Al2O3/4H-SiC MOS structures.
Insights into adsorption, diffusion, and reactions of atomic nitrogen on a highly oriented pyrolytic graphite surface
Authors: Wang Yingqi , Nieman Reed , Minton Timothy K. , Guo Hua
Published: February 2021

To gain insight into the nitrogen-related gas-surface reaction dynamics on carbon-based thermal protection systems of hypersonic vehicles, we have investigated the adsorption, diffusion, and reactions of atomic nitrogen, N(4S), on the (0001) face of graphite using periodic density functional theory with a dispersion corrected functional. The atomic nitrogen is found to bind with pristine graphite at a bridge site, with a barrier of 0.88 eV for diffusing to an adjacent bridge site. Its adsorption energy at defect sites is significantly higher, while that between graphene layers is lower. The formation of N2 via Langmuir–Hinshelwood (LH) and Eley–Rideal (ER) mechanisms was also investigated. In the LH pathway, the recombinative desorption of N2 proceeds via a transition state with a relatively low barrier (0.53 eV). In addition, there is a metastable surface species, which is capable of trapping the nascent N2 at low surface temperatures as a result of the large energy disposal into the N–N vibration. The desorbed N2 is highly excited in both of its translational and vibrational degrees of freedom. The ER reaction is direct and fast, and it also leads to translationally and internally excited N2. Finally, the formation of CN from a defect site is calculated to be endoergic by 2.75 eV. These results are used to rationalize the results of recent molecular beam experiments.
Trivalent chromium isotopes in the eastern tropical North Pacific oxygen-deficient zone
Authors: Huang Tianyi , Moos Simone B. , Boyle Edward A.
Published: February 2021

Significance

Chromium isotopes have been used to study ancient earth atmospheric oxygen levels and seem promising as a paleoredox proxy. However, few studies have focused on its cycling in the modern ocean. Here we analyzed samples from oxygen-deficient zones and investigated how chromium speciation and isotopes respond to extremely low oxygen environments, which helps to unravel the chromium redox cycling and the associated isotopic fractionation. The isotopic composition of trivalent chromium in the eastern tropical North Pacific oxygen-deficient zones is lighter than total dissolved chromium and residual hexavalent chromium. This finding supports the preferential reduction of isotopically light Cr found in theoretical and experimental studies and is fundamental to the usage of Cr isotopes as a paleoredox proxy.
Differential biosynthesis and cellular permeability explain longitudinal gibberellin gradients in growing roots
Authors: Rizza Annalisa , Tang Bijun , Stanley Claire E. , Grossmann Guido , Owen Markus R. , Band Leah R. , Jones Alexander M.
Published: February 2021

Significance

Growth hormones are mobile chemicals that exert considerable influence over how multicellular organisms like animals and plants take on their shape and form. Of particular interest is the distribution of such hormones across cells and tissues. In plants, one of these hormones, gibberellin (GA), is known to regulate cell multiplication and cell expansion to increase the rate at which roots grow. In this work, biosensor measurements were combined with theoretical models to elucidate the biochemical mechanisms that direct GA distribution and how these patterns relate to root growth. Our detailed understanding of how GA distributions are controlled in roots should prove a valuable model for understanding the makings of the many other hormone distributions that influence how plants grow.
Selenomethionine as an expressible handle for bioconjugations
Authors: Flood Dillon T. , Hintzen Jordi C. J. , Knouse Kyle W. , Hill David E. , Lu Chenxi , Cistrone Philip A. , Chen Jason S. , Otomo Takanori , Dawson Philip. E.
Published: February 2021

Significance

The manipulation of proteins in a site-selective manner underpins much of modern protein chemistry. A careful evaluation of selenomethionine benzylation led to the identification of a highly efficient bromobenzyl linker for protein bioconjugation. This selenonium-forming ligation reaction can efficiently link proteins to other complex molecules such as synthetic peptides, polymers, or reactive handles. The selenonium product is sufficiently stable at physiological pH, yet is efficiently cleaved by glutathione at intracellular concentrations. Selenomethionine benzylation is a broadly applicable tool for engineering of complex macromolecules.
Inhibitors of cullin-RING E3 ubiquitin ligase 4 with antitumor potential
Authors: Wu Kenneth , Huynh Khoi Q. , Lu Iris , Moustakim Moses , Miao Haibin , Yu Clinton , Haeusgen Matthew J. , Hopkins Benjamin D. , Huang Lan , Zheng Ning , Sanchez Roberto , DeVita Robert J. , Pan Zhen-Qiang
Published: February 2021

Significance

Cullin-RING E3 ubiquitin ligases (CRLs) direct protein degradation to impact a myriad of physiological and pathological processes including cancer. This work reports the small-molecule compounds 33-11 and KH-4-43 as inhibitors of E3 CRL4 with anticancer potential. These compounds have provided an opportunity for developing tool compounds to address mechanistic and phenotypic questions about CRL4 in biochemical, cell-based, and animal studies. The results of correlation studies between cullin4 protein level and the compounds’ cytotoxic response as well as cullin4 depletion experiments suggest a role for low E3 abundance in sensitizing tumor cells for apoptosis. Collectively, the 33-11/KH-4-43–based CRL4 inhibitors may provide new exploitable therapeutic opportunities to target a subset of tumor lines characterized by low CUL4 expression.
The DUF1013 protein TrcR tracks with RNA polymerase to control the bacterial cell cycle and protect against antibiotics
Authors: Delaby Marie , Varesio Lydia M. , Degeorges Laurence , Crosson Sean , Viollier Patrick H.
Published: February 2021

Significance

Control of transcription is fundamental to cell cycle progression and the generation of dispersal cells in bacteria. Several cell cycle regulatory proteins controlling transcription initiation have been identified in the alphaproteobacteriumCaulobacter crescentus, a model system for cell cycle studies. Our screen forC. crescentuscell cycle mutants unearthed an uncharacterized protein, TrcR, as the founding member of the conserved DUF1013 family of proteins. TrcR and its orthologs associate with initiating and elongating RNA polymerase (RNAP), and the association with elongating RNAP is prevented upon addition of the RNAP inhibitor rifampicin. TrcR-deficient cells suffer from pleiotropic cell cycle defects, including an insufficiency in the master cell cycle regulator CtrA, and antibiotic sensitivity that are suppressed by mutations in RNAP.
Waveguide evanescent waves based structured illumination microscopy with compact structure and flexible design
Authors: Li Zhenyan , Kong Weijie , Wang Changtao , Pu Mingbo , Luo Yunfei , Liu Xiangzhi , Du Wenjuan , Ma Xiaoliang , Li Xiong , Luo Xiangang
Published: February 2021

We propose a waveguide-based structured illumination microscopy (SIM) method for super-resolution surface imaging, which can exceed the 2-fold diffraction-limit improvement in traditional linear SIM by employing surface evanescent waves interference patterns. The planar waveguide structure is illuminated by grating coupled focused beams, which avoid a large adiabatic taper area and ensures a small footprint. Moreover, Blind-SIM algorithm is adopted in image reconstruction to avoid sophisticated control for the illumination field. In this designed waveguide structure, the resolution of sparse fluorescent beads improved from 246 nm to 64 nm (3.8-fold improvement) in a 5 × 5 μm2 field of view (FOV). Two beads with an 80 nm gap were resolved with a 45% dip and the resolution of diffraction-limited image of dense object was also enhanced. This method exploits a more compact waveguide structure that is easier and cheaper to fabricate, and the flexibility in design helps to improve the structure with wider FOV and higher imaging resolution.
Experimental demonstration and mechanism of mitigating reentry blackout via surface catalysis effects
Authors: Takasawa Hideto , Takahashi Yusuke , Oshima Nobuyuki , Kihara Hisashi
Published: February 2021

The reentry blackout phenomenon, which is the communication cut-off between the re-entry vehicle and ground station, is a crucial problem that needs to be addressed. To improve safety during reentry, a new mitigation method was proposed using the surface catalysis effect. However, this method has not been investigated extensively by experimental methods. In this study, we experimentally demonstrated the mitigation method using a 1 MW arc-heated wind tunnel and numerically clarified the mitigation mechanism. As a demonstration experiment, communication tests were conducted to compare the two cases. In the first case, a ceramic surface was used as a low catalytic wall, whereas in the second case, a copper surface was used as a high catalytic wall in the arc-heated wind tunnel. The experimental results indicated that the blackout occurred when alumina was used as the low catalytic wall. On the other hand, for the high catalytic wall using copper, blackout was avoided. The tests were reproduced in the wind tunnel using a numerical simulation technique. From the simulation results, the mitigation mechanism suggested that: (a) the number of nitrogen and oxygen atoms decreased due to catalysis; (b) forward reactions of electron impact ionization were suppressed due to the decrease in the number of atoms; and (c) the suppression of reactions decreased the number of electrons, thereby mitigating the reentry blackout. In addition, the numerical simulations performed on the reentry plasma around the re-entry capsule suggested that the mitigation mechanisms between the arc-heated wind flow and reentry plasma were similar despite the different airflow conditions.
A signal analysis and identification scheme for an online multiphase micron-sized particle analyzer system
Authors: Wang Fuhai , Cao Hongjian , Wang Pingping , Guo Xiaokang , Han Jinlong , Dong Haifeng , Zhang Xiangping , Wang Xiaodong
Published: February 2021

Online microparticle detection is of utmost importance for industrial production. This paper proposes a signal processing and feature identification strategy to achieve particle size statistics for online measurement in a three-phase stirred tank reactor based on the electrical sensing zone (ESZ) method. Signal denoising and de-interference are achieved using the wavelet soft threshold method combined with mathematical morphological filtering. Pulse selection is implemented using pulse width limiting conditions. The key features that distinguish the pulse waveforms are defined based on the differences in the motion characteristics of the different types of particles through the aperture. Finally, the unsupervised classification algorithm balanced iterative reducing and clustering using hierarchies clustering is employed to distinguish the pulsed features between hard particles and bubbles. The results show that the particle size distribution identified by this strategy agrees with offline measurements indicating the effectiveness of the scheme. The effects of electromagnetic noise and the interference of small bubbles that approximate the particle size in solution in the online, in-situ measurement task are solved. This study scheme has a guiding and facilitating role in applying the ESZ principle to the industrial online measurement environment.
Use of nanostructured alumina thin films in multilayer anti-reflective coatings
Authors: Reuna Jarno , Aho Arto , Isoaho Riku , Raappana Marianna , Aho Timo , Anttola Elina , Hietalahti Arttu , Tukiainen Antti , Guina Mircea
Published: February 2021

A new method for modification of planar multilayer structures to create nanostructured aluminum oxide anti-reflection coatings is reported. The method is non-toxic and low-cost, being based on treatment of the coating with heated de-ionized water after the deposition of aluminum oxide. The results show that the method provides a viable alternative for attaining a low reflectance ARC. In particular, a low average reflectivity of ∼3.3% is demonstrated in a broadband spectrum extending from 400 nm to 2000 nm for ARCs deposited on GaInP solar-cells, the typical material used as top-junction in solar cell tandem architectures. Moreover, the process is compatible with volume manufacturing technologies used in photovoltaics, such as ion beam sputtering and electron beam evaporation.
Thermal boundary resistance at graphene-pentacene interface explored by a data-intensive approach
Authors: Wang Xinyu , Fan Hongzhao , Han Dan , Hong Yang , Zhang Jingchao
Published: February 2021

As the machinery of artificial intelligence matures in recent years, there has been a surge in applying machine learning (ML) techniques for material property predictions. Artificial neural network (ANN) is a branch of ML and has gained increasing popularity due to its capabilities of modeling complex correlations among large datasets. The interfacial thermal transport plays a significant role in the thermal management of graphene-pentacene based organic electronics. In this work, the thermal boundary resistance (TBR) between graphene and pentacene is comprehensively investigated by classical molecular dynamics simulations combined with the ML technique. The TBR values along the a, b and c directions of pentacene at 300 K are 5.19 ± 0.18 × 10−8 m2 K W−1, 3.66 ± 0.36 × 10−8 m2 K W−1 and 5.03 ± 0.14 × 10−8 m2 K W−1, respectively. Different architectures of ANN models are trained to predict the TBR between graphene and pentacene. Two important hyperparameters, i.e. network layer and the number of neurons are explored to achieve the best prediction results. It is reported that the two-layer ANN with 40 neurons each layer provides the optimal model performance with a normalized mean square error loss of 7.04 × 10−4. Our results provide reasonable guidelines for the thermal design and development of graphene-pentacene electronic devices.
A synergistic interplay between dopant ALD cycles and film thickness on the improvement of the ferroelectricity of uncapped Al:HfO2 nanofilms
Authors: Yao Lulu , Liu Xin , Cheng Yonghong , Xiao Bing
Published: February 2021

The Al:HfO2 ferroelectric nanofilms with different total thicknesses and distributions of Al-rich strips are prepared using atomic layer deposition (ALD) in an uncapped configuration. The synergistic interplay between the number of Al-rich layers and the thickness of total film offers the additional flexibility to boost the ferroelectricity of the resulting Al:HfO2 nanofilms. By carefully optimizing both the ALD cycles for dopant layer and the total film thickness in the preparation, the HfO2 nanofilms in post-deposition annealing can exhibit excellent ferroelectricity. The highest remanent polarization (2Pr) of 51.8 μC cm−2 is obtained in a 19.4 nm thick Al:HfO2 nanofilm at the dopant concentration of 11.1 mol% with a three ALD cycles for Al-rich strips. Remarkable remanent polarization value observed in the uncapped electrode clamping film paves a new way to explore the origin of ferroelectricity in hafnium oxide nanofilms. The observed ferroelectricity of the nanofilm is affected neither by the presence of an interface between the upper electrode and the film nor the choices of the materials of upper electrode in the measurement, ensuring a high flexibility in the designing and fabrication of the relevant devices in the future.
Computer-aided diagnosis of ground glass pulmonary nodule by fusing deep learning and radiomics features
Authors: Hu Xianfang , Gong Jing , Zhou Wei , Li Haiming , Wang Shengping , Wei Meng , Peng Weijun , Gu Yajia
Published: February 2021

Objectives. This study aims to develop a computer-aided diagnosis (CADx) scheme to classify between benign and malignant ground glass nodules (GGNs), and fuse deep leaning and radiomics imaging features to improve the classification performance. Methods. We first retrospectively collected 513 surgery histopathology confirmed GGNs from two centers. Among these GGNs, 100 were benign and 413 were malignant. All malignant tumors were stage I lung adenocarcinoma. To segment GGNs, we applied a deep convolutional neural network and residual architecture to train and build a 3D U-Net. Then, based on the pre-trained U-Net, we used a transfer learning approach to build a deep neural network (DNN) to classify between benign and malignant GGNs. With the GGN segmentation results generated by 3D U-Net, we also developed a CT radiomics model by adopting a series of image processing techniques, i.e. radiomics feature extraction, feature selection, synthetic minority over-sampling technique, and support vector machine classifier training/testing, etc. Finally, we applied an information fusion method to fuse the prediction scores generated by DNN based CADx model and CT-radiomics based model. To evaluate the proposed model performance, we conducted a comparison experiment by testing on an independent testing dataset. Results. Comparing with DNN model and radiomics model, our fusion model yielded a significant higher area under a receiver operating characteristic curve (AUC) value of 0.73 ± 0.06 (P < 0.01). The fusion model generated an accuracy of 75.6%, F1 score of 84.6%, weighted average F1 score of 70.3%, and Matthews correlation coefficient of 43.6%, which were higher than the DNN model and radiomics model individually. Conclusions. Our experimental results demonstrated that (1) applying a CADx scheme was feasible to diagnosis of early-stage lung adenocarcinoma, (2) deep image features and radiomics features provided complementary information in classifying benign and malignant GGNs, and (3) it was an effective way to build DNN model with limited dataset by using transfer learning. Thus, to build a robust image analysis based CADx model, one can combine different types of image features to decode the imaging phenotypes of GGN.
Motility-induced clustering and meso-scale turbulence in active polar fluids
Authors: Worlitzer Vasco M , Ariel Gil , Be’er Avraham , Stark Holger , Bär Markus , Heidenreich Sebastian
Published: February 2021

Meso-scale turbulence was originally observed experimentally in various suspensions of swimming bacteria, as well as in the collective motion of active colloids. The corresponding large scale dynamical patterns were reproduced in a simple model of a polar fluid, assuming a constant density of active particles. Recent, more detailed studies in a variety of experimental realizations of active polar fluids revealed additional interesting aspects, such as anomalous velocity statistics and clustering phenomena. Those phenomena cannot be explained by currently available models for active polar fluids. Herein, we extend the continuum model suggested by Dunkel et al to include density variations and a local feedback between the local density and self-propulsion speed of the active polar particles. If the velocity decreases strong enough with the density, a linear stability analysis of the resulting model shows that, in addition to the short-wavelength instability of the original model, a long-wavelength instability occurs. This is typically observed for high densities of polar active particles and is analogous to the well-known phenomenon of motility-induced phase separation (MIPS) in scalar active matter. We determine a simple phase diagram indicating the linear instabilities and perform systematic numerical simulations for the various regions in the corresponding parameter space. The interplay between the well understood short-range instability (leading to meso-scale turbulence) and the long-range instability (associated with MIPS) leads to interesting dynamics and novel phenomena concerning nucleation and coarsening processes. Our simulation results display a rich variety of novel patterns, including phase separation into domains with dynamically changing irregularly shaped boundaries. Anomalous velocity statistics are observed in all phases where the system segregates into regions of high and low densities. This offers a simple explanation for their occurrence in recent experiments with bacterial suspensions.
A high-performance broadband terahertz absorber based on multilayer graphene squares
Authors: Liu Wenwen , Song Zhengyong , Wang Weihua
Published: February 2021

The efficient electromagnetic absorber is highly demanded in device applications. A big challenge is to design the absorber of very thin thickness and broad bandwidth, which is even more difficult at terahertz regime. In this article, we propose and numerically (finite element method, FEM) demonstrate a high-performance broadband absorber with near-perfect absorption over terahertz band based on multilayer graphene squares. The absorber consists of four graphene layers in which the width of the square is gradually increased, and a bottom gold layer separated by a dielectric spacer. The proposed structure can achieve above 90% wave absorption for the frequencies from 1.45 THz to 4.35 THz, with a bandwidth of 2.9 THz and the bandwidth fraction of 100%. Because of symmetry of the structure, this terahertz absorber is polarization insensitive and can work at a large angle range of oblique incidence, for instance absorptance can be maintained nearly unchanged up to 40° for transverse electric polarization and up to 45° for transverse magnetic polarization. Except for the layer stacking, our design is very easy to be realized in experiment, since only the simple square shape and a uniform 0.4 eV Fermi level are used in our design, which may play an important role in future terahertz device applications.
Response of primary auditory neurons to stimulation with infrared light in vitro
Authors: Brown William G A , Needham Karina , Begeng James M , Thompson Alexander C , Nayagam Bryony A , Kameneva Tatiana , Stoddart Paul R
Published: February 2021

Objective. Infrared light can be used to modulate the activity of neuronal cells through thermally-evoked capacitive currents and thermosensitive ion channel modulation. The infrared power threshold for action potentials has previously been found to be far lower in the in vivo cochlea when compared with other neuronal targets, implicating spiral ganglion neurons (SGNs) as a potential target for infrared auditory prostheses. However, conflicting experimental evidence suggests that this low threshold may arise from an intermediary mechanism other than direct SGN stimulation, potentially involving residual hair cell activity. Approach. Patch-clamp recordings from cultured SGNs were used to explicitly quantify the capacitive and ion channel currents in an environment devoid of hair cells. Neurons were irradiated by a 1870 nm laser with pulse durations of 0.2–5.0 ms and powers up to 1.5 W. A Hodgkin-Huxley-type model was established by first characterising the voltage dependent currents, and then incorporating laser-evoked currents separated into temperature-dependent and temperature-gradient-dependent components. This model was found to accurately simulate neuronal responses and allowed the results to be extrapolated to stimulation parameter spaces not accessible during this study. Main results. The previously-reported low in vivo SGN stimulation threshold was not observed, and only subthreshold depolarisation was achieved, even at high light exposures. Extrapolating these results with our Hodgkin-Huxley-type model predicts an action potential threshold which does not deviate significantly from other neuronal types. Significance. This suggests that the low-threshold response that is commonly reported in vivo may arise from an alternative mechanism, and calls into question the potential usefulness of the effect for auditory prostheses. The step-wise approach to modelling optically-evoked currents described here may prove useful for analysing a wider range of cell types where capacitive currents and conductance modulation are dominant.
Enhancing detection of steady-state visual evoked potentials using channel ensemble method
Authors: Yan Wenqiang , Du Chenghang , Luo Dan , Wu YongCheng , Duan Nan , Zheng Xiaowei , Xu Guanghua
Published: February 2021

Objective. This study proposed and evaluated a channel ensemble approach to enhance detection of steady-state visual evoked potentials (SSVEPs). Approach. Collected multi-channel electroencephalogram signals were classified into multiple groups of new analysis signals based on correlation analysis, and each group of analysis signals contained signals from a different number of electrode channels. These groups of analysis signals were used as the input of a training-free feature extraction model, and the obtained feature coefficients were converted into feature probability values using the softmax function. The ensemble value of multiple sets of feature probability values was determined and used as the final discrimination coefficient. Main results. Compared with canonical correlation analysis, likelihood ratio test, and multivariate synchronization index analysis methods using a standard approach, the recognition accuracies of the methods using a channel ensemble approach were improved by 5.05%, 3.87%, and 3.42%, and the information transfer rates (ITRs) were improved by 6.00%, 4.61%, and 3.71%, respectively. The channel ensemble method also obtained better recognition results than the standard algorithm on the public dataset. This study validated the efficiency of the proposed method to enhance the detection of SSVEPs, demonstrating its potential use in practical brain–computer interface (BCI) systems. Significance. A SSVEP-based BCI system using a channel ensemble method could achieve high ITR, indicating great potential of this design for various applications with improved control and interaction.
A novel liquid lithium jet-cooled finger-type divertor target concept for fusion power plant application
Authors: Wang Zhen , Zhang Shichao , Chen Zhibin , Jia Jiangtao , Chao Chen
Published: February 2021

The divertor target is the most thermally loaded plasma-facing component in a foreseen DEMO reactor and beyond, which has to tolerate the peak high heat fluxes of up to ∼20 MW m−2 produced by intense plasma bombardment, radiation and nuclear heating. However, none of current designs including water-cooled and helium-cooled concepts can satisfy this requirement. Motivated by the excellent power removal capacity of liquid metal coolant and combined with the structure characteristics of the finger-type helium-cooled target, a novel concept of liquid Li jet-cooled finger-type divertor target for DEMO reactors was proposed in this paper. The performance analysis, including thermal-hydraulics analysis, mechanical analysis and MHD effects analysis, have shown that the proposed design can withstand 20 MW m−2 heat load because the temperatures of the structural materials remain within the thermal rules and the maximum thermo-mechanical stress in the VM-W thimble is approximately 484 MPa appearing in the round corner, which is below the 3S
m limit at the corresponding temperature. Moreover, a theoretical and empirical analysis has confirmed that MHD effects on pressure drop and heat transfer is rather limited in the design. The comparison of this new design with other representative designs including water-cooled ITER-like target design and helium-cooled modular jet target design has been made, and the results shows that the proposed liquid Li cooled target design has better performance under 20 MW m−2 high heat flux and ∼10 dpa neutron irradiation. Therefore, this design is promising to provide a new option for solving the DEMO reactor divertor heat removal issues. Certainly, a large number of R&D efforts are still needed to ensure the success of this concept, particularly in the areas of materials, fabrication and irradiation.
Retraction: Singluar Topoi of Countably Non-local, Continuously Cayley, Maximal Elements and the Continuity of Closed Elements(Journal of Physics: Conference Series
1646 012114)
Authors: Wan Fang
Published: February 2021

This article has been retracted by IOP Publishing on 18 February 2021 in light of clear evidence that it was computer generated. IOP Publishing is investigating why this was not identified during the submission and peer review process by the conference. As a member of the Committee for Publication Ethics (COPE) this has been investigated in accordance with COPE guidelines and it was agreed the article should be retracted.

Retraction published: 18 February 2021
Neutrosophic Commutative N-ideals in KU-algebras
Authors: Vasu M. , Kumar D. Ramesh
Published: February 2021

In this paper, the new concept of neutrosophic commutative N-ideal in KU-algebras is introduced, and investigated some related properties. Also, a relations between a neutrosophic N-ideal and a neutrosophic commutative N-ideal are discussed. Characterizations of a neutrosophic commutative N-ideal are considered.
The analysis of the FM/FM/1 queue with single working vacation and impatience of customers
Authors: kannadasan G. , Devi D.
Published: February 2021

This paper deals with an M/M/1 queueing system with a single working vacation and reneging of impatient customers and fuzzy parameters. For this fuzzy queueing model, researches fetch performance measure of interest such as the mean number of customer in the system during working vacation, the mean number of customers in the system during regular busy period and the mean of reneging rate of the system. Finally numerical results are presented to show the effects of system parameter.
Total and Strong Edge Colorings on Human Chain Network
Authors: Kavitha J , Anitha K
Published: February 2021

In this paper, we have determined total chromatic and strong chromatic index of human chain network.

AMS Subject classification: 05C78
D-Lucky Edge Labeling of Strong and Weak Human Chain Networks
Authors: Rajini Ram G. , Hemalatha S. , Anitha K.
Published: February 2021

In this paper, we introduce two human chain networks namely Strong human chain and weak human chain network. Also, we have determined the D-Lucky edge number of Strong human chain and Weak human chain networks. These two networks have various application in Bus topology.
Accuracy Measure On Fuzzy Near Sets
Authors: Anita Shanthi S , Valarmathi R
Published: February 2021

In this paper the concepts of fuzzy near set, fuzzy near neighborhood, lower and upper approximation of fuzzy near sets are introduced. Accuracy measures on fuzzy near sets are also established.
Privacy Protection Method of Electric Power Network Based on Blockchain
Authors: Zhang Maolin , Zhao Weihua , Shi Wei , Zhou Haiming
Published: February 2021

In order to ensure the integrity and confidentiality of power data in the era of big data, it is very important to protect the privacy of smart grid data information. Analyzing electricity big data can obtain electricity consumption habits of electricity users to guide the formulation of power supply plans. This experiment uses an asymmetric encryption algorithm. The encryption and decryption of the asymmetric encryption algorithm use two different keys to fully guarantee the security of the blockchain system. The experiment is based on the blockchain technology in photovoltaic microgrid electricity trading, which belongs to the current type of trading, which is divided into five stages. The service provider is a node of the blockchain system. All smart contracts are encrypted by the private key of both parties in the transaction and the public key of the service provider, which fully guarantees the privacy of users. The experimental data shows that the smart contract is decrypted by the private key and the public key of both parties, so as to obtain the relevant information of the transaction and make the corresponding power dispatch work during the transaction period.The blockchain system solves the security and privacy issues of both parties in the absence of a third-party intermediary. Therefore, the use of blockchain technology can achieve a higher degree of automation for point-to-point power transactions.
PLC Control System of Pneumatic Manipulator Automatic Assembly Line Based on Cloud Computing Platform
Authors: Zhou Yucheng , Li Yifei
Published: February 2021

With the development of science and technology, cloud computing, big data and artificial intelligence and other new technologies have been applied in all aspects of life. The traditional manual tracking and processing production process has many defects. The application of computer technology to the production line to realize automatic production has the characteristics of high efficiency and integration. This paper studies the PLC control system of pneumatic robot automatic assembly line based on cloud computing platform system. In the research, we use PCL system to scan the data of automatic assembly of pneumatic manipulator processed by cloud computing platform, and write the program into the memory of PCL. At the same time, we connect the field input signal and the controlled actuator to the input end of the input module and the output end of the output module. The user can realize the automatic assembly by running the program. Compared with the number of Pneumatic Manipulators produced by manual production line, the system in this paper has high efficiency and superior performance. Thus, the PLC control system of pneumatic manipulator automatic assembly line based on cloud computing platform can improve the production efficiency.
RETRACTED: Development and Innovation of Music Course Teaching Mode Based on Big Data
Authors: Chen XinYu
Published: February 2021

The development direction of online teaching is personalized and customized teaching based on user needs. Applying big data technology to the online network teaching platform can effectively solve the problems of the huge and chaotic number of teaching resources, the difficulty of user selection, the weak management of the network learning process, the inefficient use of teaching resources, and the lack of user role sense. The purpose of this article is to explore the development and innovation of music curriculum teaching models based on big data. This paper studies the modern network music teaching platform based on big data, realizes the user demand discovery of music teaching platform and optimizes the push of music teaching resources, and realizes the full use of music teaching resources. Starting from five dimensions of user attributes, learning roles, learning process, learning objects and learning tasks, this paper analyzes the user portraits of modern online music teaching platforms based on big data and expresses them based on ontology technology. This article is based on current scholars’ theoretical foundation and practical application research on education big data and smart classroom model, through the previous literature review and analysis, research on the popularization of smart classroom model and actual observation of existing smart classroom models. For the verification of the practical effects of music teaching cases using this model, the author used questionnaire and interview methods to investigate teachers and students, and conducted investigations on teachers from basic information, classroom application and effects, and classroom satisfaction.. Research shows that 29% of teachers are very satisfied with the application of this model, and 16% of teachers are generally satisfied. It can be known that most teachers are quite satisfied with the “smart classroom” teaching model under the big data environment.
Research on Furniture Design System Based on Big Data and Information Technology
Authors: Liao Xiayan , Song Yongjun
Published: February 2021

With the rapid development of my country’s real estate and other pillar industries and the acceleration of urbanization. The furniture industry is also showing a trend of rapid development. At present, Chinese traditional furniture has long been unable to meet the needs of consumers in some functional designs. Based on this, this paper proposes a furniture design system based on big data and information technology. Make full use of the existing network environment, hardware equipment, and software technology to build a furniture product big data cloud platform that can meet the needs of business development on the basis of ensuring that the core business structure is advanced, efficient and stable. This paper studies the huge changes that the home design system will face under the influence of big data, and conducts an in-depth analysis of the industrial environment, operation mode, information transmission security and other characteristics of the home system under the background of the big data era. Research shows that under the background of the era of big data, the establishment of a big data platform for furniture products is facing new development opportunities. The development of electronic information technology provides strong support for platform construction. Utilize electronic information technology to continuously aggregate furniture product information from various channels, deeply analyze the status of furniture products, and explore furniture product quality risks, thereby building a furniture product big data cloud platform.
Digital Financial Transaction Security Based on Blockchain Technology
Authors: Song Huitong , Chen Yansheng
Published: February 2021

Blockchain technology is currently recognized as the most potential new key technology, it can bring earth shaking changes, it is expected to trigger a new round of technological innovation and industrial change, and cause market attention. The purpose of this paper is to study the security of digital financial transactions based on blockchain technology. Firstly, the security of sdte is analyzed, and the DoS attacks that each role may launch, the attacks that a single role may send, and the attacks that can be launched by multiple roles in collusion are analyzed. It shows that sdte can resist these attacks and has strong security. Then, the related environment of the system test is described. Then, the performance test and analysis are carried out from the key security transmission, the execution of smart contract in the trusted environment SGX and the total running time. The experimental results show that the extra time consumed by using the k-nearest neighbor (KNN) algorithm to process data is less than 0.45s, At the same time, the additional cost brought by the system is also acceptable.