bluuebunny/crossref_metadata_2025 huggingface dataset:
Mobility and quasi-ballistic charge carrier transport in graphene field-effect transistors
Authors: Harrysson Rodrigues Isabel , Rorsman Niklas , Vorobiev Andrei
Published: December 2022

The optimization of graphene field-effect transistors (GFETs) for high-frequency applications requires further understanding of the physical mechanisms concerning charge carrier transport at short channel lengths. Here, we study the charge carrier transport in GFETs with gate lengths ranging from 2 μm down to 0.2 μm by applying a quasi-ballistic transport model. It is found that the carrier mobility, evaluated via the drain–source resistance model, including the geometrical magnetoresistance effect, is more than halved with decreasing the gate length in the studied range. This decrease in mobility is explained by the impact of ballistic charge carrier transport. The analysis allows for evaluation of the characteristic length, a parameter of the order of the mean-free path, which is found to be in the range of 359–374 nm. The mobility term associated with scattering mechanisms is found to be up to 4456 cm2/Vs. Transmission formalism treating the electrons as purely classical particles allows for the estimation of the probability of charge carrier transport without scattering events. It is shown that at the gate length of 2 μm, approximately 20% of the charge carriers are moving without scattering, while at the gate length of 0.2 μm, this number increases to above 60%.
Artificial optoelectronic synapse based on epitaxial Ba0.6Sr0.4TiO3 thin films memristor for neuromorphic computing and image recognition
Authors: Wang Jingjuan , Shao Yiduo , Li Changliang , Liu Baoting , Yan Xiaobing
Published: December 2022

Electronic synaptic devices with photoelectric sensing function are becoming increasingly important in the development of neuromorphic computing system. Here, we present a photoelectrical synaptic system based on high-quality epitaxial Ba0.6Sr0.4TiO3 (BST) films in which the resistance ramp characteristic of the device provides the possibility to simulate synaptic behavior. The memristor with the Pt/BST/Nb:SrTiO3 structure exhibits reliable I–V characteristics and adjustable resistance modulation characteristics. The device can faithfully demonstrate synaptic functions, such as potentiation and depression, spike time-dependent plasticity, and paired pulse facilitation, and the recognition accuracy of handwritten digits was as high as 92.2%. Interestingly, the functions of visual perception, visual memory, and color recognition of the human eyes have also been realized based on the device. This work will provide a strong candidate for the neuromorphic computing hardware system of photoelectric synaptic devices.
Magnetic-free unidirectional polarization rotation and free-space optical isolators and circulators
Authors: Liu Lifeng , Zhang Ying , Zhang Shicheng , Qian Jun , Gong Shangqing , Niu Yueping
Published: December 2022

Optical nonreciprocity is an essential concept in optical signal processing and communication. The traditional way to achieve nonreciprocity is using magneto-optical nonreciprocal polarization rotation, which is incompatible with existing on-chip integration due to the applied magnetic field. Here, we theoretically and experimentally realize unidirectional polarization rotation with a magnetic-free mechanism using atomic ensembles. Free-space isolators and circulators are further formed based on the nonreciprocity of polarization rotation. As only one direction of the signal changes its polarization, the forward transmission and backward isolation can be adjusted separately. Compared with the existing magnetic-free circulators that rely on high-Q factor cavities or Mach–Zehnder interferometers, we experimentally realized circulators in free space. This dramatically simplifies the magnetic-free circulator structure and provides better stability.
The influence of crystallographic texture on structural and electrical properties in ferroelectric Hf0.5Zr0.5O2
Authors: Lee Younghwan , Broughton Rachel A. , Hsain H. Alex , Song Seung Keun , Edgington Patrick G. , Horgan Madison D. , Dowden Amy , Bednar Amanda , Lee Dong Hyun , Parsons Gregory N. , Park Min Hyuk , Jones Jacob L.
Published: December 2022

Ferroelectric (Hf,Zr)O2 thin films have attracted increased interest from the ferroelectrics community and the semiconductor industry due to their ability to exhibit ferroelectricity at nanoscale dimensions. The properties and performance of the ferroelectric (Hf,Zr)O2 films generally depend on various factors such as surface energy (e.g., through grain size or thickness), defects (e.g., through dopants, oxygen vacancies, or impurities), electrodes, interface quality, and preferred crystallographic orientation (also known as crystallographic texture or simply texture) of grains and/or domains. Although some factors affecting properties and performance have been studied extensively, the effects of texture on the material properties are still not understood. Here, the influence of texture of the bottom electrode and Hf0.5Zr0.5O2 (HZO) films on properties and performance is reported. The uniqueness of this work is the use of a consistent deposition process known as Sequential, No-Atmosphere Processing (SNAP) that produces films with different preferred orientations yet minimal other differences. The results shown in this study provide both new insight on the importance of the bottom electrode texture and new fundamental processing-structure–property relationships for the HZO films.
Effects of ratchet surfaces on inclined thermal convection
Authors: Jiang Hechuan , Wang Dongpu , Cheng Yu , Hao Huageng , Sun Chao
Published: December 2022

The influence of ratchets on inclined convection is explored within a rectangular cell (aspect ratio Γx=1 and Γy=0.25) by experiments and simulations. Measurements are conducted over a wide range of tilting angles (0.056≤β≤π/2 rad) at a constant Prandtl number (Pr=4.3) and Rayleigh number (Ra=5.7×109). We found that the arrangement of ratchets on the conducting plate determines the dynamics of inclined convection, i.e., when the large scale circulation (LSC) flows along the smaller slopes of the ratchets (case A), the change of the heat transport efficiency is smaller than 5% as the tilting angle increases from 0 to 4π/9 rad; when the LSC moves toward the steeper slope side of the ratchets (case B), the heat transport efficiency decreases rapidly with the tilting angle larger than blue π/9 rad. Through the analysis of the flow properties, we give a physical explanation for the observations. As the tilting angle increases, the heat carrier gradually changes from the thermal plumes to the LSC, resulting in different dynamical behavior. In addition, the distribution of the local heat transport also validates the explanation quantitatively. The present work gives insight for the controlling inclined convection using the asymmetric ratchet structures.
Investigation of the fluctuating velocity in a single-cell tornado-like vortex based on coherent structure extraction
Authors: Zhang Han , Wang Hao , Xu Zidong , Liu Zhenqing , Khoo Boo Cheong
Published: December 2022

Fluctuating velocity plays an essential role in tornadic winds and the induced transient loads, while its characteristics are rarely considered in existing tornado models. Based on the coherent structure extraction technology, this study investigates the characteristics of the fluctuating velocity in a single-cell tornado-like vortex (TLV) and proposes a unified wind spectrum formula accordingly. First, the performance of proper orthogonal decomposition (POD) and dynamic mode decomposition is compared and validated using synthetic vortices. A single-cell TLV is then generated by large eddy simulation. The relationship between the fluctuating velocity and the coherent structures is analyzed. Finally, a wind spectrum formula is obtained from the fluctuating velocity reconstructed by the first two POD modes that are almost unchanged with height. Thus, it is a unified formula suitable for different heights. The results show that at a lower height in the single-cell TLV, more than 90% of the velocity fluctuation is induced by vortex wandering and size variation. The first two POD modes can accurately reconstruct the fluctuating velocity with an error of less than 8%. The power spectral density of the reconstructed fluctuating velocity agrees well with the Kaimal wind spectrum in the low-frequency subrange and the proposed formula in the high-frequency subrange.
A constitutive model for sheared dense fiber suspensions
Authors: Khan Monsurul , More Rishabh V. , Ardekani Arezoo M.
Published: December 2022

We propose a constitutive model to predict the viscosity of fiber suspensions, which undergoes shear thinning, at various volume fractions, aspect ratios, and shear stresses/rates. We calibrate the model using the data from direct numerical simulation and prove the accuracy by predicting experimental measurements from the literature. We use a friction coefficient decreasing with the normal load between the fibers to quantitatively reproduce the experimentally observed shear thinning in fiber suspensions. In this model, the effective normal contact force, which is directly proportional to the bulk shear stress, determines the effective friction coefficient. A rise in the shear stress reduces the effective friction coefficient in the suspension. As a result, the jamming volume fraction increases with the shear stress, resulting in a shear thinning in the suspension viscosity. Moreover, we extend the model to quantify the effects of fiber volume fraction and aspect ratio in the suspension. We calibrate this model using the data from numerical simulations for the rate-controlled shear flow. Once calibrated, we show that the model can be used to predict the relative viscosity for different volume fractions, shear stresses, and aspect ratios. The model predictions are in excellent agreement with the available experimental measurements from the literature. The findings of this study can potentially be used to tune the fiber size and volume fraction for designing the suspension rheology in various applications.
Bone marrow-derived IGF-1 orchestrates maintenance and regeneration of the adult skeleton
Authors: Wang Jianfang , Zhu Qiaoling , Cao Dandan , Peng Qiqi , Zhang Xiaoying , Li Chong , Zhang Chen , Zhou Bo O. , Yue Rui
Published: December 2022

Insulin-like growth factor I (IGF-1) is a key regulator of tissue growth and development in response to growth hormone stimulation. In the skeletal system, IGF-1 derived from osteoblasts and chondrocytes are essential for normal bone development; however, whether bone marrow (BM)-resident cells provide distinct sources of IGF-1 in the adult skeleton remains elusive. Here, we show that BM stromal cells (BMSCs) and megakaryocytes/platelets (MKs/PLTs) express the highest levels of IGF-1 in adult long bones. Deletion of
Igf1
from BMSCs by Lepr-Cre leads to decreased bone formation, impaired bone regeneration, and increased BM adipogenesis. Importantly, reduction of BMSC-derived IGF-1 contributes to fasting-induced marrow fat accumulation. In contrast, deletion of
Igf1
from MKs/PLTs by Pf4-Cre leads to reduced bone formation and regeneration without affecting BM adipogenesis. To our surprise, MKs/PLTs are also an important source of systemic IGF-1. Platelet-rich plasma (PRP) from

Pf4-Cre; Igf1
f/f

mice showed compromised osteogenic potential both in vivo and in vitro, suggesting that MK/PLT-derived IGF-1 underlies the therapeutic effects of PRP. Taken together, this study identifies BMSCs and MKs/PLTs as two important sources of IGF-1 that coordinate to maintain and regenerate the adult skeleton, highlighting reciprocal regulation between the hematopoietic and skeletal systems.
Atf7ip and Setdb1 interaction orchestrates the hematopoietic stem and progenitor cell state with diverse lineage differentiation
Authors: Wu Jiaxin , Li Juan , Chen Kang , Liu Guolong , Zhou Yating , Chen Wenqi , Zhu Xiangzhan , Ni Terri T. , Zhang Bianhong , Jin Daqing , Li Dali , Kang Lan , Wu Yuxuan , Zhu Ping , Xie Peng , Zhong Tao P.
Published: December 2022

Hematopoietic stem and progenitor cells (HSPCs) are a heterogeneous group of cells with expansion, differentiation, and repopulation capacities. How HSPCs orchestrate the stemness state with diverse lineage differentiation at steady condition or acute stress remains largely unknown. Here, we show that zebrafish mutants that are deficient in an epigenetic regulator Atf7ip or Setdb1 methyltransferase undergo excessive myeloid differentiation with impaired HSPC expansion, manifesting a decline in T cells and erythroid lineage. We find that Atf7ip regulates hematopoiesis through Setdb1-mediated H3K9me3 modification and chromatin remodeling. During hematopoiesis, the interaction of Atf7ip and Setdb1 triggers H3K9me3 depositions in hematopoietic regulatory genes includingcebpβandcdkn1a, preventing HSPCs from loss of expansion and premature differentiation into myeloid lineage. Concomitantly, loss of Atf7ip or Setdb1 derepresses retrotransposons that instigate the viral sensor Mda5/Rig-I like receptor (RLR) signaling, leading to stress-driven myelopoiesis and inflammation. We find that ATF7IP or SETDB1 depletion represses human leukemic cell growth and induces myeloid differentiation with retrotransposon-triggered inflammation. These findings establish that Atf7ip/Setdb1-mediated H3K9me3 deposition constitutes a genome-wide checkpoint that impedes the myeloid potential and maintains HSPC stemness for diverse blood cell production, providing unique insights into potential intervention in hematological malignancy.
The lncRNA LUCAT1 is elevated in inflammatory disease and restrains inflammation by regulating the splicing and stability of NR4A2
Authors: Vierbuchen Tim , Agarwal Shiuli , Johnson John L. , Galia Liraz , Lei Xuqiu , Stein Karina , Olagnier David , Gaede Karoline I. , Herzmann Christian , Holm Christian K. , Heine Holger , Pai Athma , O’Hara Hall Aisling , Hoebe Kasper , Fitzgerald Katherine A.
Published: December 2022

The nuclear long non-coding RNA LUCAT1 has previously been identified as a negative feedback regulator of type I interferon and inflammatory cytokine expression in human myeloid cells. Here, we define the mechanistic basis for the suppression of inflammatory gene expression by LUCAT1. Using comprehensive identification of RNA-binding proteins by mass spectrometry as well as RNA immunoprecipitation, we identified proteins important in processing and alternative splicing of mRNAs as LUCAT1-binding proteins. These included heterogeneous nuclear ribonucleoprotein C, M, and A2B1. Consistent with this finding, cells lacking LUCAT1 have altered splicing of selected immune genes. In particular, upon lipopolysaccharide stimulation, the splicing of the nuclear receptor 4A2 (NR4A2) gene was particularly affected. As a consequence, expression of NR4A2 was reduced and delayed in cells lacking LUCAT1. NR4A2-deficient cells had elevated expression of immune genes. These observations suggest that LUCAT1 is induced to control the splicing and stability of NR4A2, which is in part responsible for the anti-inflammatory effect of LUCAT1. Furthermore, we analyzed a large cohort of patients with inflammatory bowel disease as well as asthma and chronic obstructive pulmonary disease. In these patients, LUCAT1 levels were elevated and in both diseases, positively correlated with disease severity. Collectively, these studies define a key molecular mechanism of LUCAT1-dependent immune regulation through post-transcriptional regulation of mRNAs highlighting its role in the regulation of inflammatory disease.
Ultrafast spectra and kinetics of human green-cone visual pigment at room temperature
Authors: Dhankhar Dinesh , Salom David , Palczewski Krzysztof , Rentzepis Peter M.
Published: December 2022

Rhodopsin is the pigment that enables night vision, whereas cone opsins are the pigments responsible for color vision in bright-light conditions. Despite their importance for vision, cone opsins are poorly characterized at the molecular level compared to rhodopsin. Spectra and kinetics of the intermediate states of human green-cone visual pigment (mid-wavelength sensitive, or MWS opsin) were measured and compared with the intermediates and kinetics of bovine rhodopsin. All the major intermediates of the MWS opsin were recorded in the picosecond to millisecond time range. Several intermediates in MWS opsin appear to have characteristics similar to the intermediates of bovine rhodopsin; however, there are some marked differences. One of the most striking differences is in their kinetics, where the kinetics of the MWS opsin intermediates are slower compared to those of the bovine rhodopsin intermediates.
A self-powered and broadband UV PIN photodiode employing a NiOx layer and a β-Ga2O3 heterojunction
Authors: Vasquez Jose Manuel Taboada , Ashai Aasim , Lu Yi , Khandelwal Vishal , Rajbhar Manoj , Kumar Mritunjay , Li Xiaohang , Sarkar Biplab
Published: December 2022

Crucial commercial and space applications require the detection of broadband ultraviolet (UV) rays spanning from UV-A to UV-C. In this study, the authors demonstrate a broadband UV photodetector employing a p-type NiOx layer and an n-type β-Ga2O3 heterostructure in PIN configuration for the first time. Simulations are conducted to optimize the doping concentration and thickness of the NiOx layer, ensuring that (a) a reasonable depletion width is maintained within the NiOx layer for UV-A and UV-B light absorption; (b) anode ohmic contacts are formed on the nondepleted NiOx film, and (c) >70% of the UV-C light is absorbed by β-Ga2O3. The optimized NiOx/β-Ga2O3 PIN photodiode exhibits good responsivity to incident light wavelengths in the UV-A, UV-B, and UV-C regions. While the NiOx layer is considered to be responsible for providing good photoresponsivity in the UV-A and UV-B regions, a highly resistive (near-intrinsic) β-Ga2O3 layer is required for the absorption of incident UV-C light. A record detectivity of >1011 cm Hz0.5 W−1 for the UV-B and UV-C regions and >1010 cm Hz0.5 W−1 for the UV-A region is observed in the NiOx/β-Ga2O3 heterostructure PIN photodiode during the self-powered operation. The results presented in this study are promising and instigate device design strategies for (ultra)wide bandgap semiconductor-based broadband UV PIN photodetectors.
Experimental investigation of CO2 conversion in Boudouard reaction driven by an atmospheric-pressure microwave plasma torch
Authors: Wu Yue , Li Shou-Zhe , Niu Yu-Long , Yan Hui-Jie , Yang Dezheng , Zhang Jialiang
Published: December 2022

An atmospheric-pressure microwave plasma torch (APMPT) is employed to drive Boudouard reaction [C(s) + CO2(g) → 2CO(g)] to convert CO2 into CO with storable chemical energy. In this experiment, the solid carbon is placed in the downstream of the afterglow of carbon dioxide APMPT, which is enclosed in reaction chamber, thereby the reaction occurs in the environment with a plenty of the active species and the large enthalpy. The conversion and energy efficiency are experimentally determined by measuring the change of the gas composition, which is analyzed with a Fourier transformation infrared spectrometer and gas chromatograph. The variations of conversion and energy efficiency are investigated with respect to the plasma state, which is tuned by changing microwave power, gas flow rate, and Ar-CO2 mixture ratio, and the different forms of carbon material. And the high conversion efficiency is obtained with use of the herbaceous type of biomass as carbon material and by increasing microwave power, however, the large percentage of CO2 in carrier gas and increasing gas flow rate impose a negative influence on CO2 conversion.
Response embedded atom model potential of Pb at finite temperature: application on the dislocation mobility
Authors: Li Pan , Huang Yongfeng , Wang Kun , Xiao Shifang , Yao Songlin , Hu Wangyu
Published: December 2022

Dislocation is a major carrier of plastic deformation for metal materials and are crucial. Understanding the mechanism of dislocation motion is beneficial for understanding the plastic deformation of materials under dynamic loading. In this work, a new response EAM (REAM) potential is developed for the applications under high pressure and finite temperature conditions. We use the REAM potential to investigate the behaviors of edge and screw dislocations in Pb by molecular dynamics (MD) simulations, and compare it with two commonly used EAM potentials. Specially, we examine the influence of the stacking fault energy and the temperature-dependent elastic constants on the dislocation motions. Our results show that the temperature-dependent elastic constants do not considerably affect the dislocation motion at the linear region of low stress, while the stacking fault energy plays a significant role. In the nonlinear region, the stacking fault energy and elastic constant together influence the dislocation motion. In subsonic and low transonic regimes, the dislocation width oscillates with time, but eventually fluctuates around equilibrium width.
On the superstring-inspired quantum correction to the Starobinsky model of inflation
Authors: Ketov Sergei V. , Pozdeeva Ekaterina O. , Vernov Sergey Yu.
Published: December 2022

Superstring/M-theory is the theory of quantum gravity that can provide the UV-completion to viable inflation models. We modify the Starobinsky inflation model by adding the Bel-Robinson tensor Tμνλρ
squared term proposed as the leading quantum correction inspired by superstring theory. The (R + 1/6m
2
R
2 - β/8m
6
T
2) model under consideration has two parameters: the inflaton mass m and the string-inspired positive parameter β. We derive the equations of motion in the Friedmann-Lemaitre-Robertson-Walker universe and investigate its solutions. We find the physical bounds on the value of the parameter β by demanding the absence of ghosts and consistency of the derived inflationary observables with the measurements of the cosmic microwave background radiation.
Studies on modified power law inflation
Authors: Paul Prasenjit , Sengupta Rikpratik , Ray Saibal
Published: December 2022

In this study, we evaluate power law inflation (PLI) with a monomial potential and obtain a novel exact solution. It is well known that the conventional PLI with an exponential potential is inconsistent with the Planck data. Unlike the standard PLI, the present model does not encounter the graceful exit problem, and the results agree fairly well with recent observations. In our analysis, we calculate the spectral index and the tensor-to-scalar ratio, both of which agree very well with recent observational data and are comparable with those of other modified inflationary models. The employed technique reveals that the large cosmological constant decreases with the expansion of the universe in the case of the PLI. The coupling of the inflaton with gravitation is the primary factor in this technique. The basic assumption here is that the two metric tensors in the gravitational and inflaton parts correspond to different conformal frames, which contradicts with the conventional PLI, where the inflaton is directly coupled with the background metric tensor. This fact has direct applications to different dark energy models and the assisted quintessence theory.
Determination of Distance, Extinction, Mass, and Age for Stars in LAMOST DR7
Authors: Wang Jianling , Cao Zihuang , Huang Yang , Yuan Haibo
Published: December 2022

Large scale spectroscopic surveys such as that using Large-sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) have collected spectra of millions stars in the Milky Way. Utilizing this huge sample of stars to study the assembling history and structure of our Galaxy requires accurate estimates of distance, extinction, age, and mass for individual stars. Combining the parallax constraint from Gaia EDR3 with Bayesian inference, we have estimated the distance and extinction for stars observed in LAMOST DR7, as well as the stellar mass and age for evolved stars in this data release. We validated the accuracies of the stellar parameters by comparing our results against various measurements, including the star-pair technique, asteroseismology, globular clusters, and isochrone fits to main sequence stars and subgiants. This is a valuable catalog of stellar parameters under a Bayesian framework estimated using the data from Gaia EDR3 and LAMOST spectroscopic data. With this data set we explored the stellar population of the Galactic massive substructure Gaia-Sausage-Enceladus (GSE). The kinematically selected members of GSE have a median metallicity of [Fe/H] = −1.29 and a median age of 11.6 Gyr.
Interfacial dynamics of GaP/Si(100) heterostructure grown by molecular beam epitaxy
Authors: Wei Tieshi , Li Xuefei , Li Zhiyun , Yang Wenxian , Wu Yuanyuan , Xing Zhiwei , Lu Shulong
Published: December 2022

The atomic structure and surface chemistry of GaP/Si(100) heterostructure with different pre-layers grown by molecular beam epitaxy are studied. It is found that GaP epilayer with Ga-riched pre-layers on Si(100) substrate has regular surface morphology and stoichiometric abrupt heterointerfaces from atomic force microscopes (AFMs) and spherical aberration-corrected transmission electron microscopes (ACTEMs). The interfacial dynamics of GaP/Si(100) heterostructure is investigated by X-ray photoelectron spectroscopy (XPS) equipped with an Ar gas cluster ion beam, indicating that Ga pre-layers can lower the interface formation energy and the bond that is formed is more stable. These results suggest that Ga-riched pre-layers are more conducive to the GaP nucleation as well as the epitaxial growth of GaP material on Si(100) substrate.
Effect of warpage on the electronic structure and optical properties of bilayer germanene
Authors: Xiong Qihang , Cen Weifu , Wu Xingtong , Chen Cong
Published: December 2022

The electronic structure and optical properties of bilayer germanene under different warpages are studied by the first-principles method of density functional theory. The effects of warpages on the electronic structure and optical properties of bilayer germanene are analyzed. The results of the electronic structure study show that the bottom of the conduction band of bilayer germanene moves to the lower energy direction with the increase of warpages at the K point, and the top of the valence band stays constant at the K point, and so the band gap decreases with the increase of warpage. When the warpage is 0.075 nm, the top of the valence band of bilayer germanene changes from K point to G point, and the bilayer germanene becomes an indirect band gap semiconductor. This is an effective means to modulate the conversion of bilayer germanene between direct band gap semiconductor and indirect band gap semiconductor by adjusting the band structure of bilayer germanene effectively. The study of optical properties shows that the effect of warpage on the optical properties of bilayer germanene is mainly distributed in the ultraviolet and visible regions, and the warpage can effectively regulate the electronic structure and optical properties of bilayer germanene. When the warpage is 0.069 nm, the first peak of dielectric function and extinction coefficient is the largest, and the energy corresponding to the absorption band edge is the smallest. Therefore, the electron utilization rate is the best when the warpage is 0.069 nm.
Influence of architecture and temperature of alkali atom vapor cells on absorption spectra
Authors: Liu Yali , Li Wei , Li Yudong , Li Xiaokuan , Feng Liangsen , Li Xinliang
Published: December 2022

Chip-sized alkali atom vapor cells with high hermeticity are successfully fabricated through deep silicon etching and two anodic bonding processes. A self-built absorption spectrum testing system is used to test the absorption spectra of the rubidium atoms in alkali atom vapor cells. The influence of silicon cavity size, filling amount of rubidium atoms and temperature on the absorption spectra of rubidium atom vapor in the atom vapor cells are studied in depth through a theoretical analysis. This study provides a reference for the design and preparation of high quality chip-sized atom vapor cells.
Surface instability of static liquid metal in magnetized fusion plasma
Authors: Somboonkittichai N. , Zuo G.Z.
Published: December 2022

Understanding surface instability in magnetized fusion plasma supports the appropriate implementation and handling of liquid metal as plasma facing components (PFCs) in future fusion reactors. A Lagrange equation describing a viscous liquid surface deformation in a magnetized plasma is derived using Rayleigh’s method. Its solution justifies the general instability criterion and helps in characterizing the key interactions driving such instability under fusion conditions. Surface tension and gravity, especially with the poloidal angles of the lower part of a plasma chamber, mainly stabilize the liquid surface at small and large disturbance wavelengths, respectively. The sheath electric field and the external tangential magnetic field cause the liquid surface to disintegrate at an intermediate wavelength. Practically, a magnetic confinement fusion (MCF) device requires a strong magnetic field for confinement. The study suggests that such a strong field dominates the rest and governs instability. In addition, this implies that the configuration of a static planar free liquid surface is difficult to adopt as a candidate for handling the liquid metal as PFCs in next step MCF devices.
Effect of Undersea Parameters on Reliability of Underwater Acoustic Sensor Network in Shallow Water
Authors: Padmavathy N , Venkateswara Rao Ch
Published: December 2022

Underwater acoustic sensor networks have attained intensifying significance within the research communality, since they are enabling technology for wide range of applications. Typically, these networks establish connectivity (single or multi-hop) by a means of acoustic links. Acoustic communications pose several challenges due to transmission losses, fading, multipath, and effect of medium characteristics (depth, salinity, temperature and pH) on sound speed. The variation in sound speed affects the link formation, which may lead to link failures among sensor nodes. It seems to be crucial to incorporate a channel model that reflect on effect of medium and channel characteristics (absorption and transmission losses) in order to accomplish reliable communication among the links in an underwater network. In this work, an evaluation method for the two-terminal reliability of underwater sensor networks deployed in shallow water scenarios has been proposed. The methodology takes into account an acoustic channel model that distinguishes the effect of frequency and the aforementioned parameters on link formation. Two-terminal reliability analysis has been carried out by considering the effect of underwater media properties. The experimental outcomes specify that, reliability is reaches its maximum value when the temperature and salinity discrepancy with respect to depth are insignificant at lesser frequencies than that of upper frequencies.
Generation of Pulse Sequence Using EMG Signals for Application in Transfemoral Prosthesis
Authors: Babu R Dhanush , Veezhinathan Mahesh , Munirathnam Dhanalakshmi , Aishwarya V
Published: December 2022

The percentage of people having a lower leg amputation is high, and the incidence of unemployment among these amputees is likewise rising. Hence, it requires the intervention of an innovative solution to serve the function of a lost limb. Electromyogram (EMG) signals is a result of the potential generated by muscles during contraction. In this work, an attempt has been made to extract EMG signals from four set of muscle groups and the acquired signals were pre-processed and transformed to pulses to extract the contraction phase of the signal. Furthermore, the processed signals were subject to feature extraction process where in the Mean Absolute Value (MAV), Integrated EMG Feature (IEMG) and various statistical parameters associated with the signal such as the mean, median, standard deviation, variance, kurtosis, skewness was calculated in order to serve as an input to drive the stepper motor of a transfemoral prosthesis. To promote real time acquisition and control, a transfemoral socket with an ischial containment has been designed.
Pipe inspection robots: a review
Authors: John Binil , Shafeek M
Published: December 2022

Pipelines are one of the safe and most economical ways of transporting fluid matters in industries and households. These pipelines get deteriorated due to aging, internal and external corrosion, and so on. This may cause fluid leakages and may contaminate the environment. So, pipelines are inspected regularly to maintain proper functioning and cost-effectiveness. In-pipe inspection robots (IPIR) that move inside pipelines are widely used to carry out inspection operations. IPIR along with visual and other r non-destructive tests (NDT) are proven to be useful compared to manual inspection. Wheel-driven robots, track-driven robots, wall-press robots, pipe inspection gauge (PIG) robots, and many other bio-inspired designs are available. The design parameters and specializations of each type of robot will be presented in this article. Because each robot is created with different factors in mind, such as pipeline diameter, mobility, adaptability, working conditions, and so on, these robots are unique and have different constraints. These topics will be covered in depth in this article, and will ultimately aid in the selection of certain robots based on specific criteria. New design strategies in the pipe inspection industry that have yet to be explored will also be covered in depth.
Influence of Different Parameters on the Specific Wear Rate of PTFE Composites in the Steam Environment
Authors: Bhosale A B , Walame M V , Lathesh M
Published: December 2022

Carbon filled PTFE material has been used in various engineering applications due to its properties of self-lubrication and minimal porosity. In Paper Industry carbon filled PTFE composite is used as a mechanical face seal to prevent the leakage of the steam. During the sealing application, the material is subjected to the wear hence, it is necessary to determine its wear rate to compute the life of the material when subjected to different loading conditions. Researchers have studied the tribological characteristics of carbon filled PTFE composites in dry sliding conditions as well as in a humid environment. However, wear behaviour of PTFE composite material in a steam environment is yet to be explored. In present study, the research is focused on the variation of specific wear rate of two grades of Carbon filled PTFE composites in a steam environment with the change in contact pressure and sliding velocity. In order to conduct the experiment in a steam environment, a pin on disc tribometer with a steam enclosure is designed and fabricated. The two grades used in this study are 25% Carbon filled PTFE and 35% Carbon filled PTFE. It was observed that the loss due to wear for both the materials increases with the rise in contact pressure. For 35% carbon filled PTFE, the specific wear rate decreases with the increase in sliding velocity whereas it increases with increase in sliding velocity for 25% carbon filled PTFE.
Study of active magnetic bearings (AMB) on non–synchronous rotors
Authors: Teyi Nabam , Singh Sandeep
Published: December 2022

A rotor is never free from vibration owing to constant centrifugal force acting on it while rotating. A practical rotor has inherent mass unevenness flaw, or bearing misalignment flaw, or self-weight bow flaw, or presence of discontinuity or cracks flaw. If the vibrations are not controlled within limits, the rotor’s purpose of existence is lost. These vibrations can be synchronous if the frequency of vibration is equal to, or multiple of, the speed of rotation of the rotor. Or may be non-synchronous if the frequency of vibration of the rotor is not a multiple of its rotational frequency. Active magnetic bearings (AMBs) have been in use for vibration control, vibration suppression, rotor stability and condition monitoring of rotordynamic systems, since many years. A lot of authors have performed various numerical and experimental works in an AMB–rotor configuration and reported their findings. The goal of this paper is to report and present the effect of AMB solely on non–synchronous rotors for the benefit of the scientific community. Firstly, this paper briefly introduces the constructional features on AMB–rotor system. Then, the gist of every paper is written, as well as specification of the work provided in tabular form. Finally, some comments on limitations and future applications are made. The paper is separately sectioned into numerical investigations, and experimental investigations.
Compression and energy absorption properties of the truss-like lightweight materials based on symmetric groups
Authors: Ma Zhenhao , Ma Wensuo , Ma Zhenyu , Huang Zhaohua , Yang Liguang , Xu Yonghao
Published: December 2022

Truss-like lightweight materials (TLMs) have been widely used in aeronautics and astronautics, because of excellent mechanical property and superior energy absorption capability. The design of TLMs’ meso-structures was a critical task to improve its performance. Hence, a structure design method based on the symmetric groups was proposed for TLMs, and a novel hexagonal prism TLM’s meso-structure was deduced by the symmetric and translational operations of the space group P6mm. To investigate the performance of the novel TLM, the mechanical analysis model was established. The predictive equations of compression performance was proposed based on Euler–Bernoulli beam theory. The stress distribution of the novel TLM’s meso-structure under compression load was discussed by the finite element analysis method, and its compression and energy absorption properties were investigated. The simulation results were in agreement with the predictive results. In addition, the common FCC and BCC TLMs were discussed using the symmetry group analysis method, and their compression properties were predicted. The results showed that the proposed novel TLM in this study had better compression property than BCC and FCC TLMs at the same relative density.
Mechanical properties of carbon fiber reinforced with carbon nanotubes and graphene filled epoxy composites: experimental and numerical investigations
Authors: Prasanthi P Phani , Kumar M S R Niranjan , Chowdary M Somaiah , Madhav V V Venu , Saxena Kuldeep K , Mohammed Kahtan A , Khan Muhammad Ijaz , Upadhyay Gaurav , Eldin Sayed M
Published: December 2022

The mechanical properties of carbon fiber-reinforced epoxy composites were identified by adding carbon-based nano-reinforcements, such as multi-wall carbon nanotubes (CNTs) and graphene platelets (GP), into the epoxy matrix by conducting suitable experiments. The main focus of this study is to compare the tensile modulus, tensile strength, flexural modulus, flexural strength, and thermal conductivity of carbon fiber-reinforced epoxy composites with nanoparticle reinforcement. The results revealed that adding CNTs and GP nanoparticles improved the mechanical properties compared to a pure carbon fiber-reinforced plastic composite. However, compared to CNTs, the GP’s addition has increased the mechanical properties of the CFRP composite. In addition, scanning electron microscopy (SEM) images were presented to explore the microstructural characterization of carbon fiber-reinforced nanoparticle-reinforced composites. Further, using numerical studies, the transverse modulus, major and minor Poisson’s ratio of the carbon fibre reinforced with CNT and GP particle reinforcement were estimated. The current study is applied to the efficient design of nanoparticle reinforced carbon fibre reinforced composites.
Partitions of topological spaces and a new club-like principle
Authors: Carvalho Rodrigo , Fernandes Gabriel , Junqueira Lúcia
Published: December 2022

We give a new proof of the following theorem due to W. Weiss and P. Komjath: if

X
X

is a regular topological space, with character

>

b

> \mathfrak {b}

and

X
→
(
t
o
p

ω
+
1

)

ω

1

X \rightarrow (top\, \omega + 1)^{1}_{\omega }

, then, for all

α
>

ω
1

\alpha > \omega _1

,

X
→
(
t
o
p

α

)

ω

1

X \rightarrow (top\, \alpha )^{1}_{\omega }

, fixing a gap in the original one. For that we consider a new decomposition of topological spaces. We also define a new combinatorial principle

♣

F

\clubsuit _{F}

, and use it to prove that it is consistent with

¬
C
H

\neg CH

that

b

\mathfrak {b}

is the optimal bound for the character of

X
X

. In [Proc. Amer. Math. Soc. 101 (1987), pp. 767–770], this was obtained using

♢
\diamondsuit

.
Some new results about 𝑞-trinomial coefficients
Authors: Chen Yifan , Xu Chang , Wang Xiaoxia
Published: December 2022

In this paper, we present several new congruences on the

q
q

-trinomial coefficients introduced by Andrews and Baxter [J. Statist. Phys. 47 (1987), 297–330]. A new congruence on sums of central

q
q

-binomial coefficients is also established.
Distribution of moments of Hurwitz class numbers in arithmetic progressions and holomorphic projection
Authors: Kane Ben , Pujahari Sudhir
Published: December 2022

In this paper, we study moments of Hurwitz class numbers associated to imaginary quadratic orders restricted into fixed arithmetic progressions. In particular, we fix

t
t

in an arithmetic progression

t
≡
m
 

(
mod

M
)

t\equiv m\ \, \left ( \operatorname {mod} \, M \right )

and consider the ratio of the

2
k

2k

-th moment to the zeroeth moment for

H
(
4
n
−

t
2

)

H(4n-t^2)

as one varies

n
n

. The special case

n
=

p
r

n=p^r

yields as a consequence asymptotic formulas for moments of the trace

t
≡
m
 

(
mod

M
)

t\equiv m\ \, \left ( \operatorname {mod} \, M \right )

of Frobenius on elliptic curves over finite fields with

p
r

p^r

elements.
Site-specific glycosylation and single amino acid substitution dramatically reduced the immunogenicity of β-lactoglobulin
Authors: Endo Michio , Yoshida Tadashi , Ishii Keisatoi , Iwamoto Taku , Totsuka Mamoru , Hattori Makoto
Published: December 2022

To reduce the immunogenicity of β-lactoglobulin (BLG), we prepared recombinant BLG which has both site-specific glycosylation and single amino acid substitution (D28N/P126A), and expressed it in the methylotrophic yeast Pichia pastoris by fusion of the cDNA to the sequence coding for the α-factor signal peptide from Saccharomyces cerevisiae. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) analysis indicated that the D28N/P126A was conjugated with a ∼4 kDa high-mannose chain. D28N/P126A retained ∼61% of the retinol-binding activity of BLG. Structural analyses by circular dichroism (CD) spectra, intrinsic fluorescence, and Enzyme-linked immunosorbent assay (ELISA) with monoclonal antibodies indicated that the surface structure of BLG was slightly changed by using protein engineering techniques, but D28N/P126A was covered by high-mannose chains and substituted amino acid without substantial disruption of native conformation. Antibody responses to the D28N/P126A considerably reduced in C57BL/6 mice. We conclude that inducing both site-specific glycosylation and single amino acid substitution simultaneously is an effective method to reduce the immunogenicity of BLG.
Tracking the path of predator recognition in a predator-naive population of the pond snail
Authors: Batabyal Anuradha , Lukowiak Ken
Published: December 2022

Organisms evolve adaptive strategies to adjust to rapidly changing environmental stressors. Predation pressure is one of the strongest selective forces and organisms respond to predatory threats via innate and learned responses. We utilized a natural, experimental set-up, where two lakes Stoney and Margo in Canada containing natural populations of the prey Lymnaea stagnalis differed in the presence and absence of an invasive, predatory Northern crayfish, Faxonius virilis. We exploited the contrast in the predation backgrounds of the snail populations from the two lakes to test, 1) predator recognition in predator-experienced snails is innate, (2) predator-naive snails learn to detect a novel invasive predator, and 3) learning about a novel predator gets transmitted to the successive generations. We quantified predator fear memory formation using a higher-order learning paradigm called configural learning. We found that 1) predator recognition in predator-experienced snails is innate, 2) predator-naive snails learned to recognize the novel predator even after a brief exposure to predator cues highlighting the role of learning in combating invasive predators and the critical time-window during development that accounts for predator recognition, and 3) the learning and predator detection mechanism in predator-naive snails are not transmitted to successive generations. The population variation observed in the predator-detection mechanism may be due to the past and current experience of predators in one population over the other. We find an interesting study system to address how fear learning occurs and prospective future directions to understand the mechanism of innate fear recognition from a learned fear recognition.
Systematic analysis of alternative splicing in time course data using Spycone
Authors: Lio Chit Tong , Grabert Gordon , Louadi Zakaria , Fenn Amit , Baumbach Jan , Kacprowski Tim , List Markus , Tsoy Olga
Published: December 2022

Motivation

During disease progression or organism development, alternative splicing may lead to isoform switches that demonstrate similar temporal patterns and reflect the alternative splicing co-regulation of such genes. Tools for dynamic process analysis usually neglect alternative splicing.

Results

Here, we propose Spycone, a splicing-aware framework for time course data analysis. Spycone exploits a novel IS detection algorithm and offers downstream analysis such as network and gene set enrichment. We demonstrate the performance of Spycone using simulated and real-world data of SARS-CoV-2 infection.

Availability and implementation

The Spycone package is available as a PyPI package. The source code of Spycone is available under the GPLv3 license at https://github.com/yollct/spycone and the documentation at https://spycone.readthedocs.io/en/latest/.

Supplementary information

Supplementary data are available at Bioinformatics online.