bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of sinusoidal waveform and frequency on space charge characteristics of polyimide
Authors: Ren Hanwen , Tanaka Yasuhiro , Miyake Hiroaki , Li Qingmin , Gao Haoyu , Li Chengqian , Wang Zhongdong
Published: May 2021

The charge phenomena under sine and half‐wave sine voltages within the frequency range of 500 Hz are studied here. Based on the pulsed electro‐acoustic method, the traditional circuit design under high‐frequency voltages is first analysed. It is found that the selection of a 186 pF protection capacitor and a 333 kΩ protection resistor can ensure that the actual voltage applied to the sample is consistent with the expected input. Based on this design, experimental results show that the polarity of the charge accumulated in the depth of the sample is determined by that of the upper electrode. Comparison results under special voltages with different amplitudes and frequencies indicate that the amount of accumulated charge under sine voltages are larger than those under positive and negative half‐wave sine and DC conditions, and the samples under lower‐frequency conditions show more charge accumulation. The maximum electric field strengths appear at 90 and 270 degrees of the sine voltage with a frequency of 10 Hz, and their values are 68.55 and 81.82 kV/mm, respectively. Therefore, the charge characteristics are easily affected by the voltage’s waveform and frequency parameters. The results obtained here can provide guidance for the application of insulating materials under special voltage environments.
All‐fibre phase shifter based on tapered fibre coated with MoWS2‐rGO
Authors: Tan Sin Jin , Ahmad Harith , Tiu Zian Cheak
Published: May 2021

In this work, an all‐fibre phase shifter using tapered fibre coated with molybdenum tungsten disulfide ‐ reduced graphene oxide (MoWS2‐rGO) is demonstrated. The large evanescent field of tapered fibre allows MoWS2‐rGO to absorb injected light from a 1400‐nm pump. It subsequently modifies the refractive index of both an MoWS2‐rGO solution and tapered fibre because of the thermo‐optic effect. A maximum wavelength shift of 2.489 nm is observed and the equivalent phase shift is 0.91π. The efficiency of the phase shifter is calculated at 0.0175 nm/mW. The proposed phase shifter is beneficial for a variety of applications, specifically for future optical beam‐forming networks and all optical signal processing devices.
A multi‐modal heterogeneous data mining algorithm using federated learning
Authors: Wei Xianyong
Published: May 2021

In disease diagnosis, the classification accuracy based on multi‐modal models is usually higher than single‐modal models. However, in the process of multimodal data fusion, how to reasonably solve the heterogeneity problem and better extract the information between different modal data has attracted the attention of scholars. Federated learning is an efficient machine learning method that can expand between multiple parameters or multiple computing nodes. It has been applied successfully in the financial industry and cross‐industry cooperation. In this paper, a novel algorithm to disease diagnosis model based on federated learning is proposed. The model not only cleverly solves heterogeneous problems, but also excavates information between different modal data to promote the model to be more robust and discriminative. The experiment results show that the proposed model has better performance than traditional fusion algorithms. Notably, compared with other models, this model converges faster and requires less computation.
Simulating the infrared sky with a SPRITZ
Authors: Bisigello L. , Gruppioni C. , Feltre A. , Calura F. , Pozzi F. , Vignali C. , Barchiesi L. , Rodighiero G. , Negrello M.
Published: May 2021

Aims. Current hydrodynamical and semi-empirical simulations of galaxy formation and evolution have difficulties in reproducing the number densities of infrared-detected galaxies. Therefore, a phenomenological simulation tool that is new and versatile is necessary to reproduce current and predict future observations at infrared (IR) wavelengths.

Methods. In this work we generate simulated catalogues starting from the Herschel IR luminosity functions of different galaxy populations to consider different populations of galaxies and active galactic nuclei (AGN) in a consistent way. We associated a spectral energy distribution and physical properties, such as stellar mass, star formation rate, and AGN contribution, with each simulated galaxy using a broad set of empirical relations. We compared the resulting simulated galaxies, extracted up to z = 10, with a broad set of observational relations.

Results. Spectro-Photometric Realisations of IR-Selected Targets at all-z (SPRITZ) simulations allow us to obtain, in a fully consistent way, simulated observations for a broad set of current and future facilities with photometric capabilities as well as low-resolution IR spectroscopy, such as the James Webb Space Telescope (JWST) or the Origin Space Telescope (OST). The derived simulated catalogue contains galaxies and AGN that by construction reproduce the observed IR galaxy number density, but this catalogue also agrees with the observed number counts from UV to far-IR wavelengths, the observed stellar mass function, the star formation rate versus stellar mass plane, and the luminosity function from the radio to X-ray wavelengths. The proposed simulation is therefore ideal to make predictions for current and future facilities, in particular, but not limited to, those operating at IR wavelengths.
COALAS
Authors: Jin S. , Dannerbauer H. , Emonts B. , Serra P. , Lagos C. D. P. , Thomson A. P. , Bassini L. , Lehnert M. , Allison J. R. , Champagne J. B. , Indermühle B. , Norris R. P. , Seymour N. , Shimakawa R. , Casey C. M. , De Breuck C. , Drouart G. , Hatch N. , Kodama T. , Koyama Y. , Macgregor P. , Miley G. , Overzier R. , Pérez-Martínez J. M. , Rodríguez-Espinosa J. M. , Röttgering H. , Sánchez Portal M. , Ziegler B.
Published: May 2021

We report a detailed CO(1−0) survey of a galaxy protocluster field at z = 2.16, based on 475 h of observations with the Australia Telescope Compact Array. We constructed a large mosaic of 13 individual pointings, covering an area of 21 arcmin2 and ±6500 km s−1 range in velocity. We obtained a robust sample of 46 CO(1−0) detections spanning z = 2.09 − 2.22, constituting the largest sample of molecular gas measurements in protoclusters to date. The CO emitters show an overdensity at z = 2.12 − 2.21, suggesting a galaxy super-protocluster or a protocluster connected to large-scale filaments of ∼120 cMpc in size. We find that 90% of CO emitters have distances >0.′5−4′ to the center galaxy, indicating that small area surveys would miss the majority of gas reservoirs in similar structures. Half of the CO emitters have velocities larger than escape velocities, which appears gravitationally unbound to the cluster core. These unbound sources are barely found within the R200 radius around the center, which is consistent with a picture in which the cluster core is collapsed while outer regions are still in formation. Compared to other protoclusters, this structure contains a relatively higher number of CO emitters with relatively narrow line widths and high luminosities, indicating galaxy mergers. We used these CO emitters to place the first constraint on the CO luminosity function and molecular gas density in an overdense environment. The amplitude of the CO luminosity function is 1.6 ± 0.5 orders of magnitude higher than that observed for field galaxy samples at z ∼ 2, and one order of magnitude higher than predictions for galaxy protoclusters from semi-analytical SHARK models. We derive a high molecular gas density of 0.6 − 1.3 × 109 M⊙ cMpc−3 for this structure, which is consistent with predictions for cold gas density of massive structures from hydro-dynamical DIANOGA simulations.
Turbulence and wave transmission at an ICME-driven shock observed by the Solar Orbiter and Wind
Authors: Zhao L.-L. , Zank G. P. , He J. S. , Telloni D. , Hu Q. , Li G. , Nakanotani M. , Adhikari L. , Kilpua E. K. J. , Horbury T. S. , O’Brien H. , Evans V. , Angelini V.
Published: May 2021

Aims.An interplanetary coronal mass ejection (ICME) event was observed by the Solar Orbiter at 0.8 AU on 2020 April 19 and by Wind at 1 AU on 2020 April 20. Futhermore, an interplanetary shock wave was driven in front of the ICME. Here, we focus on the transmission of the magnetic fluctuations across the shock and we analyze the characteristic wave modes of solar wind turbulence in the vicinity of the shock observed by both spacecraft.

Methods.The observed ICME event is characterized by a magnetic helicity-based technique. The ICME-driven shock normal was determined by magnetic coplanarity method for the Solar Orbiter and using a mixed plasma and field approach for Wind. The power spectra of magnetic field fluctuations were generated by applying both a fast Fourier transform and Morlet wavelet analysis. To understand the nature of waves observed near the shock, we used the normalized magnetic helicity as a diagnostic parameter. The wavelet-reconstructed magnetic field fluctuation hodograms were used to further study the polarization properties of waves.

Results.We find that the ICME-driven shock observed by Solar Orbiter and Wind is a fast, forward oblique shock with a more perpendicular shock angle at the Wind position. After the shock crossing, the magnetic field fluctuation power increases. Most of the magnetic field fluctuation power resides in the transverse fluctuations. In the vicinity of the shock, both spacecraft observe right-hand polarized waves in the spacecraft frame. The upstream wave signatures fall within a relatively broad and low frequency band, which might be attributed to low frequency MHD waves excited by the streaming particles. For the downstream magnetic wave activity, we find oblique kinetic Alfvén waves with frequencies near the proton cyclotron frequency in the spacecraft frame. The frequency of the downstream waves increases by a factor of ∼7–10 due to the shock compression and the Doppler effect.
Plasma Levels of Big Endothelin-1 Are Associated with Renal Insufficiency and In-Hospital Mortality of Immune Thrombotic Thrombocytopenic Purpura
Authors: Lu Ruinan , Zheng X. Long
Published: May 2021

Immune thrombotic thrombocytopenic purpura (iTTP) is caused by severe deficiency of plasma ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) activity. Despite advances in early diagnosis and management, the mortality rate of acute iTTP remains high in a large part of world where access to some of the most novel therapies is limited. To determine the role of plasma big endothelin-1 (bigET-1) or its bioactive product ET-1 as a biomarker and/or a pathogenic factor in acute iTTP, plasma levels of bigET-1 were determined using an immunoassay in patients with iTTP on admission and during remission, as well as in healthy controls; moreover, the biological effect of ET-1 in thrombus formation was determined by a microfluidic assay. We show that plasma levels of bigET-1 were dramatically increased in patients with acute iTTP on admission, which was significantly decreased during clinical response/remission; elevated admission levels of plasma bigET-1 were associated with low estimated glomerular filtration rate, the need for intensive care unit admission or intubation, and in-hospital mortality. Moreover, an addition of a bioactive product ET-1 to cultured endothelial cells in a microfluidic channel significantly accelerated the rate of thrombus formation under arterial flow. Our results demonstrate for the first time a potential role of measuring plasma bigET-1 in patients with acute iTTP in assessing the disease severity and risk of in-hospital mortality, which may help stratify patients for a more aggressive monitoring and therapeutic strategy; also, the bioactive ET-1, derived from bigET-1, may result in acute renal injury in TTP patient, likely through its vasoconstriction and prothrombotic properties.
A Unique Case of Concomitant Intraspinal Epidermoid Cyst and Lipoma Associated with Tethered Cord Syndrome
Authors: Jain Shrey , Vyas Medha A. , Sinha Ajit K.
Published: May 2021

Patients presenting with pain in lower back and paresthesia in lower limbs may have tethered cord causing the symptomology. Tethered cord may be associated with intradural tumors causing symptoms due to progressive increase in size. Association of tethered cord with single intradural tumor is a common occurrence but, to date, only one case has been reported of tethered cord associated with intradural lipoma and epidermoid cyst. The authors would like to present a similar case in a middle-aged patient.
Year in Review: Synopsis of Selected Articles in Neuroanesthesia and Neurocritical Care from 2020
Authors: Esmail Tariq , Subramaniam Sudhakar , Venkatraghavan Lashmi
Published: May 2021

This review is a synopsis of selected articles from neuroscience, neuroanesthesia, and neurocritical care from the year 2020 (January–December 2020). The journals reviewed include anesthesia journals, critical care medicine journals, neurology and neurosurgical journals, as well as high-impact medical journals such as the Lancet, Journal of American Medical Association, New England Journal of Medicine, and Stroke. This summary of important articles will serve to update the knowledge of anesthesiologists and other perioperative physicians who provide care to neurosurgical and neurocritical care patients. In addition, some of the important narrative reviews that are of interest to neuroanesthesiologists are also listed.
A Prospective Study and Analysis of Ventriculoperitoneal Shunt Surgery: Their Indication and Complication in a Single Tertiary Care Center
Authors: Pal Barnava , Dhar Sambuddha , Sahu Anurag , Kumari Sumita , Singh Kulwant , Bhaikhel Kamalpreet Kaur , Nalin Shrish , Singh Ashvamedh , Singh Rahul
Published: May 2021

Background Ventriculoperitoneal (VP) shunt insertion is routinely performed for the treatment of hydrocephalus due to different indications like congenital, infective, tumor, posttraumatic, and normal pressure hydrocephalus (NPH). A lot of common and rare complications following this procedure have been reported.

Objectives To analyze the clinical profile, indications, anesthetic, and postoperative complications for VP shunt surgery in our center.

Materials and Methods This prospective clinical review study was conducted in the Department of Neurosurgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi, between October 2018 to January 2020 and included 454 cases of hydrocephalus who underwent VP shunt surgery. The data was compiled and analyzed.

Results A total of 454 patients with male predominance were studied. Pediatric and adolescent patients were 48.9% (222/454). Obstructive hydrocephalus due to tumors was the etiology of 48.7% (221/454) cases. The incidence of overall shunt complications was 9.7% (44/454), of which obstruction and infection was 5.9% (27/454) and 3.1% (14/454), respectively. Factors associated with increased shunt complications include redo and infective etiology and cases having higher protein in perioperative cerebrospinal fluid (CSF) analysis. Neuronavigation, antibiotic-impregnated shunt and biventricular shunt are associated with lower complications.

Conclusion Obstructive hydrocephalus due to tumors happened to be the most common cause of VP shunt, and shunt obstruction is most common complication, especially in infective and redo cases.
Lattice dynamics and electronic properties of Heusler alloys Li2AlX (X=Ga, In): A comparison study
Authors: Dogan Emel Kilit , Gulebaglan Sinem Erden
Published: May 2021

The lattice parameters, bulk modulus, first derivative of the bulk modulus, electronic band structures, phonon dispersion curves and phonon density of states calculations for Li2AlGa and Li2AlIn Heusler alloys are performed and compared in this study using density functional theory within the generalized gradient approximation. Computed lattice parameters display a good agreement with the literature. Obtained electronic band structures of both Heusler alloys show that they are in semi-metallic structure. Phonon dispersion curves and the phonon density of states graphs are also obtained in order to study the lattice dynamics of these Heusler alloys. It is noticed that Li2AlGa and Li2AlIn Heusler alloys are dynamically stable in the ground state.
Curie–Weiss behavior of the low-temperature paramagnetic susceptibility of semiconductors doped and compensated with hydrogen-like impurities
Authors: Poklonski N. A. , Dzeraviaha A. N. , Vyrko S. A. , Zabrodskii A. G. , Veinger A. I. , Semenikhin P. V.
Published: May 2021

For the first time, a quantitative model of the Curie–Weiss behavior of a low-temperature paramagnetic susceptibility of electrically neutral donors in n-type diamagnetic covalent semiconductors is proposed. The exchange interaction between nearest two neutral donors was calculated with the use of the Heitler–London model. In this model, we take into account the change in the thermal ionization energy of donors due to the shift of the bottom of the conduction band to the bandgap with doping and compensation. The energy of the exchange spin–spin interaction between electrons localized on donors is calculated as a function of the donor concentration and the degree of their compensation by acceptors. The broadening of the donor band due to the Coulomb interaction of the nearest impurity ions was taken into account. We considered crystals of n-type germanium doped with arsenic up to the concentration close to the insulator–metal phase transition (Mott transition) and compensated with gallium. The compensation ratio K is the ratio of the concentration of compensating acceptors KN to the concentration of doping donors N. The model predicts a change in the sign of the Curie–Weiss temperature from minus to plus (a transition from the antiferromagnetic to ferromagnetic local ordering of electron spins on donors) for K ≈ 0.15–0.3, reaching its maximum positive values of ≈1.3 K for K ≈ 0.5 with the following decrease (a transition to paramagnetism) for K > 0.85. The calculated behavior of the paramagnetic susceptibility of donors is consistent with the experimental data for compensated n-Ge:As,Ga samples close to the Mott transition.
VO2 nanostripe-based thin film with optimized color and solar characteristics for smart windows
Authors: Savorianakis G. , Mita K. , Shimizu T. , Konstantinidis S. , Voué M. , Maes B.
Published: May 2021

This study presents a structuration approach to reach a high luminous transmittance (Tlum) and solar modulation efficiency (ΔTsol) of thermochromic vanadium dioxide (VO2) thin films. Before starting optical simulations, we confirm that the optical properties of monoclinic VO2 continuous films deposited by reactive magnetron sputtering show a good correspondence with numerical results. Then, calculations on ordered VO2 nanostripes demonstrate an enhanced transmittance due to the presence of vertical openings, leading to a variety of photonic effects. A series of optimizations by varying the column width, period, and film thickness establishes that 20 nm wide and 10 nm separated nanostripes have a ΔTsol of 14.2% and a Tlum of 47.6% for a film thickness of 250 nm. In comparison to a dense film without nanostructuring, the film transparency (related to Tlum) is significantly enhanced, while ΔTsol remains unchanged. Furthermore, this also translates into a favorable, less opaque color, so the geometry could be useful for various thermochromic applications, such as smart windows.
Layer dependent interlayer coherent phonon dynamics in PdSe2 films
Authors: Li Di , Fu Jibo , Suo Peng , Zhang Wenjie , Lu Bo , Lin Xian , Yan Xiaona , Li Bo , Ma Guohong , Yao Jianquan
Published: May 2021

The layered transition metal dichalcogenide has attracted tremendous attention for its unique structure and electrical and optoelectronic properties. As an emerging two-dimensional material, PdSe2 plays a key role in optoelectronic applications due to its distinct optical and tunable electrical properties. The carrier dynamic and low-frequency phonon modes and how they evolve with the number of layers are important for future device fabrication in photonics, optoelectronics, and nanomechanics. Here, by employing ultrafast optical pump–probe spectroscopy, we have investigated systematically the photocarrier dynamics as well as the thickness dependent interlayer coherent phonon modes in PdSe2 films. Two low-frequency phonon modes in PdSe2 films are identified after photoexcitation at 780 nm. The higher-frequency mode is ascribed to the interlayer breathing mode, and the lower one is assigned to the standing wave mode, and both of the mode frequencies decrease with increasing the number of layers of films. Analysis based on simple one-dimensional chain model produces interlayer force constant K = 5.74 × 1019 N/m3 for the interlayer breathing mode, and sound velocity of v = 8.27 × 104 cm/s for the standing wave mode in PdSe2 film. Our experimental finding paves the way for designing and developing PdSe2-based optoelectronic and nanomechanic devices.
Ag@mSiO2@Ag core–satellite nanostructures enhance the antibacterial and anti-inflammatory activities of naringin
Authors: Tang Min , Wang Lijun , Zhao Dan , Huang Dongwei
Published: May 2021

Bacterial infections have caused many human diseases, so effective treatment of bacterial infections is an urgent problem that needs to be solved. In this work, a multifunctional therapeutic core–satellite nanoplatform (ASAN NPs) with antibacterial and anti-inflammatory properties was designed and synthesized. First, mesoporous silica-coated silver nanoparticles (Ag NPs) with different sizes were synthesized via a simplified method that improved the stability and drug-carrying capacity of the Ag NPs. Then, the NPs were loaded with anti-inflammatory and antibacterial naringin. The characterization results showed that the ASAN NPs were successfully synthesized, with an average particle size of 110 ± 15 nm. In vitro antibacterial test results showed that the synergistic effect of Ag NPs and naringin enhanced the antibacterial activity in a dose-dependent manner. The ASAN NPs achieved high-efficiency antibacterial activity by increasing the permeability of the cell membrane, destroying the integrity of the bacteria, and significantly increasing the level of bacterial reactive oxygen species. The in vivo antibacterial results showed that the ASAN NPs had highly effective anti-infective and anti-inflammatory activities and did not show obvious side effects. Thus, ASAN NPs appear to be promising antimicrobial agents with good biocompatibility, potent antibacterial activity, and anti-inflammatory activity.
Broadband second harmonic generation in aperiodic nonlinear photonic crystals: 1D projection from 2D Vogel sunflower spiral array
Authors: Wang Nian-Mu , Huang Huang , Zhang Chao
Published: May 2021

The structure of the sunflower head can be used to realize broadband applications in optics. However, this 2D structure, with a ring-shaped reciprocal space, only has a normalized Fourier coefficient peak around 0.033, which leads to a relatively low conversion efficiency and may restrict its applications. We tried to maintain its broadband features while with larger Fourier coefficients by structure dimension reduction. We obtained an aperiodic 1D structure from a 2D Vogel sunflower spiral array by a cut-and-projection method. Workable reciprocal vector bands were found with this 1D structure in the vicinity of a pre-set central wavelength λ0 = 1.4 µm, and its peak Fourier coefficients can be 5–7 times as large as the original 2D structure. With this, we investigated broadband quasi-phase matching (QPM) second harmonic generation (SHG) in samples with different reversed ratios D. To illustrate in more detail, three samples were closely examined with D = 0.4, 0.5, and 0.6. Bandwidths of these three samples for first-order QPM SHG are 90, 70, and 30 nm, respectively, with a fundamental wave in the vicinity of λ0 = 1.4 µm. The exact SHG solution of coupled-wave equations was used in the evaluation of conversion efficiencies. Calculations showed broadband high conversion efficiency.
Effect of solidification rate and Al content on solid solution in Mg–Al–Zn alloy
Authors: Su Juan , Guo Feng , Haotian Guo , Xiaobo Gao , Haiquan Feng
Published: May 2021

Mg–Al–Zn alloys with different Al content and different cooling conditions were prepared. The solid solution content of Al and Zn in the alloy was determined by electrochemical phase separation. The results show that Al has a large amount of solid solution, while Zn has a very low amount. Al can play a role in solid solution strengthening, while Zn is very small. Al has a repulsive effect on Zn and reduces the solid solubility of Zn. The higher the Al content it has, the larger the Al solid solution and the smaller the Zn solid solution we observe. The higher the solidification cooling rate is, the greater the solid solution amount of Al and Zn is.
TRIM37 prevents formation of condensate-organized ectopic spindle poles to ensure mitotic fidelity
Authors: Meitinger Franz , Kong Dong , Ohta Midori , Desai Arshad , Oegema Karen , Loncarek Jadranka
Published: May 2021

Centrosomes are composed of a centriolar core surrounded by pericentriolar material that nucleates microtubules. The ubiquitin ligase TRIM37 localizes to centrosomes, but its centrosomal roles are not yet defined. We show that TRIM37 does not control centriole duplication, structure, or the ability of centrioles to form cilia but instead prevents assembly of an ectopic centrobin-scaffolded structured condensate that forms by budding off of centrosomes. In ∼25% of TRIM37-deficient cells, the condensate organizes an ectopic spindle pole, recruiting other centrosomal proteins and acquiring microtubule nucleation capacity during mitotic entry. Ectopic spindle pole–associated transient multipolarity and multipolar segregation in TRIM37-deficient cells are suppressed by removing centrobin, which interacts with and is ubiquitinated by TRIM37. Thus, TRIM37 ensures accurate chromosome segregation by preventing the formation of centrobin-scaffolded condensates that organize ectopic spindle poles. Mutations in TRIM37 cause the disorder mulibrey nanism, and patient-derived cells harbor centrobin condensate-organized ectopic poles, leading us to propose that chromosome missegregation is a pathological mechanism in this disorder.
Alzheimer mutant speeds APP transport
Authors: Gandy Sam , Ehrlich Michelle E.
Published: May 2021

APPS198P segregates with rare familial forms of Alzheimer’s disease and resides within exon 5, unlike 27 other mutations that reside in exons 16 or 17. In this issue, Zhang et al. (2021. J. Exp. Med.https://doi.org/10.1084/jem.20210313) show that the brains of APPS198P transgenic mice accumulate excess levels of Aβ. In cultured cells, APPS198P undergoes accelerated ER folding, leading to early arrival in late vesicular compartments, thereby enhancing generation of Aβ.
Numerical investigation of active control of tearing mode by magnetic coils and the role of Δ′
Authors: He Yuling , Liu Yueqiang , Li Li , Yang Xu , Xia Guoliang
Published: May 2021

Magnetic feedback stabilization of the tearing mode (TM) is numerically investigated, utilizing the MARS-F code (Liu et al 2000 Phys. Plasmas
7 3681) for toroidal tokamak equilibria. With control coil configurations assumed in this study, magnetic feedback partially or fully stabilizes the TM, with either vanishing or finite equilibrium pressure. The best control is achieved by the combination of internal active coils and internal poloidal sensors. The internal and external tearing indices are evaluated for the close-loop system, based on the MARS-F computed mode eigenvalue and eigenfunction, respectively. In the absence of the favorable curvature effect, these two indices are real-valued and quantitatively agree well with each other. For the equilibrium with finite pressure gradient at the mode rational surface, the favorable average curvature effect becomes important and the close-loop tearing index also becomes complex-valued, partly due to interaction of the feedback system with the dissipative wall eddy current response. Isolating the inner layer and outer region response to magnetic feedback, with either proportional or proportional-derivative actions, allows to establish that feedback stabilization of the TM occurs mainly due to modification of the behavior of the external ideal solution, further confirming the analytic result reported in He et al 2021 Phys. Plasmas
28 012504.
3D printed self-propelled composite floaters
Authors: Shabaniverki Soheila , Alvarez-Valdivia Antonio , Juárez Jaime J.
Published: May 2021

This article presents a method for fabricating millimeter scale self-propelled floaters that move under their own power in random trajectories. The floaters are fabricated using fused deposition modeling of ABS scaffolds that are encapsulated in, and subsequently dissolved from, polydimethylsiloxane. The evacuated millifluidic channels left by dissolving acrylonitrile butadiene styrene (ABS) scaffolds are filled in with an ethanol-infused polyethylene glycol diacrylate hydrogel that serves as the fuel to drive propulsion in a fluid. We examine the motion of four different shapes, finding that shapes with two open ends exhibited pulsation in their trajectory, while shapes with a single open end featured trajectories that directed it to move in circles. The mean square displacement (MSD) was constructed from these trajectories to measure the mean position variance and average velocity. The floater design with a single open end was measured to have a higher mean variance per unit time (2.9 mm2 s−1) and average velocity (4.4 mm s−1). These parameters were nearly twice as high in comparison to the slowest floater design, which had an mean variance per unit time and average velocity of 1.7 mm2 s−1 and 1.5 mm s−1, respectively. In order to show that the motion behaved in a manner that is similar to Brownian motion, we simulated the trajectories using a Langevin dynamic simulation. The result of these simulations showed excellent agreement between the measured and simulation MSD. To show the utility of these structures for mixing applications, we designed a floating spinner that completely mixes a mixture of dye and water within 12 s. Ultimately, the design process illustrated here may find use in variety of platforms that require sample mixing, cargo transport and sensing.
Contribution of joule heating and viscous dissipation on three dimensional flow of Casson model comprising temperature dependent conductance utilizing shooting method
Authors: Sohail Muhammad , Chu Yu-Ming , El-Zahar Essam R , Nazir Umar , Naseem Tahir
Published: May 2021

This report examines the flow of non-Newtonian fluids down a bilateral surface under the influence of a magneto-hydrodynamic effect that is applied in many fields seen in the applied sciences and has received the attention of researchers because of its vast usage. It is assumed that the movement of particles generated fluid due to the movement of walls in the light of horizontal and vertical directions. Thermal study is carried out by employing the contribution of Joule heating, viscous dissipation and radiation. The phenomena of variable thermal conductivity and mass diffusion coefficient are also used in the modeling of the law of conservation of energy transport and species. The contribution of Brownian thermocouple and diffusion is captured by using the Buongrino model. The impact of various impact parameters was sketched. The involvement of the various parameters is measured in terms of dimensional stress, heat rate and mass. The limitation case of the current investigation is compared with the case of the published publications and an excellent arrangement is noted. The rate of transfer of thermal energy at wall of hot surface has gained using large values of Prandtl number because of large values of Prandtl number results reduction in thermal boundary layer while ratio between momentum and thermal boundary layers called Prandtl number. Hence, reduction in thermal boundary layer (TBL) results maximum production in rate of transfer of thermal energy.
Precise and accurate cosmology with CMB×LSS power spectra and bispectra
Authors: Chen Shu-Fan , Lee Hayden , Dvorkin Cora
Published: May 2021

With the advent of a new generation of cosmological experiments that will provide high-precision measurements of the cosmic microwave background (CMB) and galaxies in the large-scale structure, it is pertinent to examine the potential of performing a joint analysis of multiple cosmological probes.
In this paper, we study the cosmological information content contained in the one-loop power spectra and tree bispectra of galaxies cross-correlated with CMB lensing.
We use the FFTLog method to compute angular correlations in spherical harmonic space, applicable for wide angles that can be accessed by forthcoming galaxy surveys.
We find that adding the bispectra and cross-correlations with CMB lensing offers a significant improvement in parameter constraints, including those on the total neutrino mass, Mν, and local non-Gaussianity amplitude, .
In particular, our results suggest that the combination of the Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST) and CMB-S4 will be able to achieve σ(Mν)=42 meV from galaxy and CMB lensing correlations, and σ(Mν)=12 meV when further combined with the CMB temperature and polarization data, without any prior on the optical depth.
The stringy origins of Galileons and their novel limit
Authors: Easson Damien , Manton Tucker , Parikh Maulik , Svesko Andrew
Published: May 2021

We show generalized Galileons — a particular subclass of
Horndeski gravity — arise from a consistent Kaluza-Klein reduction
of the low-energy effective action of heterotic string theory to
first order in α'. This suggests Horndeski theories of
gravity have a string-theoretic origin. The form of the Galileonic
terms is precisely fixed by parameters of the embedding spacetime,
so that only a specific subset of Horndeski theories is permitted by
string theory. A novel limit of the model is considered by
performing a dimensionfulrescaling of α'.
Neutrino signal dependence on gamma-ray burst emission mechanism
Authors: Pitik Tetyana , Tamborra Irene , Petropoulou Maria
Published: May 2021

Long duration gamma-ray bursts (GRBs) are among the least
understood astrophysical transients powering the high-energy
universe. To date, various mechanisms have been proposed to explain
the observed electromagnetic GRB emission. In this work, we show
that, although different jet models may be equally successful in
fitting the observed electromagnetic spectral energy distributions,
the neutrino production strongly depends on the adopted emission and
dissipation model. To this purpose, we compute the neutrino
production for a benchmark high-luminosity GRB in the internal shock
model, including a dissipative photosphere as well as three emission
components, in the jet model invoking internal-collision-induced
magnetic reconnection and turbulence (ICMART), in the case of a
magnetic jet with gradual dissipation, and in a jet with dominant
proton synchrotron radiation. We find that the expected neutrino
fluence can vary up to three orders of magnitude in amplitude and
peak at energies ranging from 104 to 108 GeV. For our
benchmark input parameters, none of the explored GRB models is
excluded by the targeted searches carried out by the IceCube and
ANTARES Collaborations. However, our work highlights the potential
of high-energy neutrinos of pinpointing the underlying GRB emission
mechanism and the importance of relying on different jet models for
unbiased stacking searches.
First-principles study on improvement of two-dimensional hole gas concentration and confinement in AlN/GaN superlattices
Authors: He Huihui , Yang Shenyuan
Published: May 2021

Using first-principles calculations based on density functional theory, we have systematically studied the influence of in-plane lattice constant and thickness of slabs on the concentration and distribution of two-dimensional hole gas (2DHG) in AlN/GaN superlattices. We show that the increase of in-plane lattice constant would increase the concentration of 2DHG at interfaces and decrease the valence band offset, which may lead to a leak of current. Increasing the thickness of AlN and/or decreasing the thickness of GaN would remarkably strengthen the internal field in GaN layer, resulting in better confinement of 2DHG at AlN/GaN interfaces. Therefore, a moderate larger in-plane lattice constant and thicker AlN layer could improve the concentration and confinement of 2DHG at AlN/GaN interfaces. Our study could serve as a guide to control the properties of 2DHG at III-nitride interfaces and help to optimize the performance of p-type nitride-based devices.
Pitman–Yor process mixture model for community structure exploration considering latent interaction patterns*
Authors: Wang Jing , Li Kan
Published: May 2021

The statistical model for community detection is a promising research area in network analysis. Most existing statistical models of community detection are designed for networks with a known type of community structure, but in many practical situations, the types of community structures are unknown. To cope with unknown community structures, diverse types should be considered in one model. We propose a model that incorporates the latent interaction pattern, which is regarded as the basis of constructions of diverse community structures by us. The interaction pattern can parameterize various types of community structures in one model. A collapsed Gibbs sampling inference is proposed to estimate the community assignments and other hyper-parameters. With the Pitman–Yor process as a prior, our model can automatically detect the numbers and sizes of communities without a known type of community structure beforehand. Via Bayesian inference, our model can detect some hidden interaction patterns that offer extra information for network analysis. Experiments on networks with diverse community structures demonstrate that our model outperforms four state-of-the-art models.
Projective representation of D
6 group in twisted bilayer graphene*
Authors: Yuan Noah F. Q.
Published: May 2021

Within the framework of continuum model, we study the projective representation of emergent D
6 point group in twisted bilayer graphene. We then construct tight-binding models of the lowest bands without and with external electromagnetic fields, based on the projective representation.
Excellent thermoelectric performance predicted in Sb2Te with natural superlattice structure*
Authors: Zhang Pei , Ouyang Tao , Tang Chao , He Chaoyu , Li Jin , Zhang Chunxiao , Zhong Jianxin
Published: May 2021

Using first-principles calculations combined with the Boltzmann transport theory, we explore the thermoelectric properties of natural superlattice (SL) structure Sb2Te. The results show that n-type Sb2Te possesses larger Seebeck coefficient of 249.59 (318.87) μV/K than p-type Sb2Te of 219.85 (210.38) μV/K and low lattice thermal conductivity of 1.25 (0.21) W/mK along the in-plane (out-of-plane) direction at 300 K. The excellent electron transport performance is mainly attributed to steeper density of state around the bottom of conduction band. The ultralow lattice thermal conductivity of Sb2Te is mainly caused by low phonon group velocity and strong anharmonicity. Further analysis shows that the decrease of group velocity comes from flatter dispersion curves which are contributed by the Brillouin-zone folding. The strong anharmonicity is mainly due to the presence of lone-pair electrons in Sb2Te. Combining such a high Seebeck coefficient with the low lattice thermal conductivity, maximum n-type thermoelectric figure of merit (ZT) of 1.46 and 1.38 could be achieved along the in-plane and out-of-plane directions at room temperature, which is higher than the reported values of Sb2Te3. The findings presented here provide insight into the transport property of Sb2Te and highlight potential applications of thermoelectric materials at room temperature.
Ultra-longer fiber cantilever taper for simultaneous measurement of temperature and relative humidity*
Authors: Li Min , Yin Jiwen , Yan Weili , Cong Aimin , Li Hongjuan , Ma Wenqiang
Published: May 2021

An ultra-longer fiber cantilever taper for simultaneous measurement of the temperature and relative humidity (RH) with high sensitivities was proposed. The structure was fabricated by using the simple and cost-effective method only including fiber cleaving, splicing, and tapering. The length of the cantilever taper is about 1.5 mm. The dip A and dip B were measured simultaneously, owing to the ultra-long length and super-fine size, the temperature sensitivities of the dip A and dip B reached as high as 127.3 pm/°C and 0 pm/°C between 25 °C and 50 °C, and the RH sensitivities are –31.2 pm/% RH and –29.2 pm/% RH with a broad RH interval ranging from 20% RH to 70% RH. Besides, the proposed structure showed good linearity in the sensing process and small temperature crosstalk. It will be found in wide applications in environmental monitoring, food processing, and industries.
Group velocity matters for accurate prediction of phonon-limited carrier mobility*
Authors: Yang Qiao-Lin , Deng Hui-Xiong , Wei Su-Huai , Luo Jun-Wei
Published: May 2021

First-principles approaches have recently been developed to replace the phenomenological modeling approaches with adjustable parameters for calculating carrier mobilities in semiconductors. However, in addition to the high computational cost, it is still a challenge to obtain accurate mobility for carriers with a complex band structure, e.g., hole mobility in common semiconductors. Here, we present a computationally efficient approach using isotropic and parabolic bands to approximate the anisotropy valence bands for evaluating group velocities in the first-principles calculations. This treatment greatly reduces the computational cost in two ways: relieves the requirement of an extremely dense
k
mesh to obtain a smooth change in group velocity, and reduces the 5-dimensional integral to 3-dimensional integral. Taking Si and SiC as two examples, we find that this simplified approach reproduces the full first-principles calculation for mobility. If we use experimental effective masses to evaluate the group velocity, we can obtain hole mobility in excellent agreement with experimental data over a wide temperature range. These findings shed light on how to improve the first-principles calculations towards predictive carrier mobility in high accuracy.
Calculation of double-β decay half-lives using an improved Primakoff-Rosen formula *
Authors: Zhi Qi-Jun , Zhang Xiao-Ping , You Ji-Lin , Zheng Qiang , Ren Zhong-Zhou
Published: May 2021

A systematic analysis on experimental data of the half-lives of nuclear double-

decays with two neutrinos (

) is performed based on the analytical formula proposed by Primakoff and Rosen. We improve the formula by considering the shell effects and refining the energy dependence of the phase-space factor. This improved formula can closely describe all available experimental half-lives of

decays, both for ground-state transitions and transitions from ground states of parent nuclei to the first

excited states of daughter nuclei. The calculated half-lives agree with the experimental data of ground-state transitions of all known eleven nuclei with an average factor of 2.3. Further predictions are provided for

-decay candidates with decay energies above 0.5 MeV. We compare different theoretical predictions and emphasize the importance of experimental measurements on the half-lives of double-

transitions between the ground state of

Ca,

Ge, and

Xe and the first

excited states of their corresponding daughter nuclei, which will be very useful for understanding the underlying mechanisms of double-

decays and for further studying the shell effects on nuclear transition matrix elements.
Grey Wolf Optimizer algorithm for solving the multi depot vehicle routing problem and its implementation
Authors: Diastivena D , Wahyuningsih S , Satyananda D
Published: May 2021

Multi Depot Vehicle Routing Problem (MDVRP) is one of Vehicle Routing Problem (VRP) variants. MDVRP is a VRP that uses more than one depot for the distribution process. In this paper, the MDVRP will be solved using the Grey Wolf Optimizer (GWO). This algorithm is inspired by hunting technique and hierarchy of grey wolves. The completion of MDVRP consists of two stages, they are grouping and routing. In the grouping stage, customers are grouped to nearest depot. In the routing stage, the route is determined at each depot using “route-first, cluster-second”. In the route-first phase a giant tour is formed by forming population array. In the cluster-second phase, a split will be conducted on the giant tour, so that a number of routes are formed with the total demand for each route does not exceed the vehicle capacity. The implementation of GWO algorithm for MDVRP was designed in Borland Delphi 7.0 programming language. The algorithm was tested using 2 depots and 9 customers formed 2 routes at each depot with a total distance of 833 km. Another test was carried out by comparing the GWO with the ACO using the Cordeau dataset. GWO gives the best result (shortest distance) than ACO.
Study of variable neighborhood descent and tabu search algorithm in VRPSDP
Authors: Christopher Y , Wahyuningsih S , Satyananda D
Published: May 2021

The application of graph theory can be used to solve distribution optimization problems, especially the Vehicle Routing Problems (VRP). One variant of VRP is the Vehicle Routing Problem with Simultaneous Delivery and Pickup (VRPSDP), which has particular constraints, namely requests, and returns, which are done simultaneously. The VRPSDP problems can be solved by a variety of algorithms, such as the tabu search algorithm and the Variable Neighborhood Descent (VND) algorithm. The basic principle of the VND algorithm is to determine the initial solution and repair the solution using the neighborhood operator. In this article, the initial solution is determined by the insertion heuristic algorithm and makes improvements using six neighborhood operators. The optimum condition of the VND algorithm is reached if there is the most optimal solution for all operators, and the solution has converged to a minimum value. The application of the VND algorithm on VRPSDP was made using Borland Delphi 7 software. The VND algorithm application program was tested using standardized data sets with 100 and 200 customers, then compared multiple routes, solutions, and gaps (%). For many customers, 100 and 200 on the two types of data sets, there are many more VND algorithm routes than the tabu search algorithm. The results of the distance solution for the four data sets show that the tabu search algorithm is smaller than the VND algorithm. The type c data set has a smaller gap compared to the type r data set for both 100 and 200 customers to test tabu search algorithms and VND algorithms.