bluuebunny/crossref_metadata_2025 huggingface dataset:
DPAM-PSPNet: ultrasonic image segmentation of thyroid nodule based on dual-path attention mechanism
Authors: Wang Shuhuan , Li Zhiqing , Liao Lingmin , Zhang Chunquan , Zhao Jiali , Sang Liang , Qian Wei , Pan GuangYao , Huang Long , Ma He
Published: July 2023

Objective. Deep learning has demonstrated its versatility in the medical field, particularly in medical image segmentation, image classification, and other forms of automated diagnostics. The clinical diagnosis of thyroid nodules requires radiologists to locate nodules, diagnose conditions based on nodule boundaries, textures and their experience. This task is labor-intensive and tiring; therefore, an automated system for accurate thyroid nodule segmentation is essential. In this study, a model named DPAM-PSPNet was proposed, which automatically segments nodules in thyroid ultrasound images and enables to segment malignant nodules precisely. Approach. In this paper, accurate segmentation of nodule edges is achieved by introducing the dual path attention mechanism (DPAM) in PSPNet. In one channel, it captures global information with a lightweight cross-channel interaction mechanism. In other channel, it focus on nodal margins and surrounding information through the residual bridge network. We also updated the integrated loss function to accommodate the DPAM-PSPNet. Main results. The DPAM-PSPNet was tested against the classical segmentation model. Ablation experiments were designed for the two-path attention mechanism and the new loss function, and generalization experiments were designed on the public dataset. Our experimental results demonstrate that DPAM-PSPNet outperforms other existing methods in various evaluation metrics. In the model comparison experiments, it achieved performance with an mIOU of 0.8675, mPA of 0.9357, mPrecision of 0.9202, and Dice coefficient of 0.9213. Significance. The DPAM-PSPNet model can segment thyroid nodules in ultrasound images with little training data and generate accurate boundary regions for these nodules.
Demonstration of machine-learning-enhanced Bayesian quantum state estimation
Authors: Lohani Sanjaya , Lukens Joseph M , Davis Atiyya A , Khannejad Amirali , Regmi Sangita , Jones Daniel E , Glasser Ryan T , Searles Thomas A , Kirby Brian T
Published: July 2023

Machine learning (ML) has found broad applicability in quantum information science in topics as diverse as experimental design, state classification, and even studies on quantum foundations. Here, we experimentally realize an approach for defining custom prior distributions that are automatically tuned using ML for Bayesian quantum state estimation methods that generally better conform to the physical properties of the underlying system than standard fixed prior distributions. Previously, researchers have looked to Bayesian quantum state tomography for advantages like uncertainty quantification, the return of reliable estimates under any measurement condition, and minimal mean-squared error. However, practical challenges related to long computation times and conceptual issues concerning how to incorporate prior knowledge most suitably can overshadow these benefits. Using both simulated and experimental measurement results, we demonstrate that ML-defined prior distributions reduce net convergence times and provide a natural way to incorporate both implicit and explicit information directly into the prior distribution. These results constitute a promising path toward practical implementations of Bayesian quantum state tomography.
Trans-Planckian effect in f(R) cosmology
Authors: Cheraghchi S , Shojai F , Abbassi M H
Published: July 2023

Apart from the assumption that the inflation started at an infinite time in the past, the more realistic initial state of the quantum fluctuations is described by a mixed quantum state imposed at a finite value of the initial time. One of the most important non-trivial vacua is the α-vacuum, which is specified by a momentum cutoff Λ U H Danielsson (2002 Phys. Rev. D
66, 023511). As a consequence, the initial condition is imposed at different initial times for the different k-modes. This modifies the amplitude of the quantum fluctuations, and thus the corresponding power spectra. In this paper, we consider the imprint of the α-vacuum state on the power spectrum of scalar perturbations in a generic f(R) gravity by assuming an ultraviolet cutoff Λ. As a specific model, we consider the Starobinsky model and find the trans-Planckian power spectrum. We find that the leading order corrections to the scalar power spectra in f(R) gravity have an oscillatory behavior as in general relativity C Armendáriz-Picón, Eugene A Lim, (2003 JCAP
12 006), and furthermore, the results are in sufficient agreement with the ΛCDM model.
Thermal production of massless dark photons
Authors: Salvio Alberto
Published: July 2023

A dark photon is predicted by several well-motivated Standard Model extensions and UV completions. Here the most general effective field theory up to dimension-six operators
describing the interactions of a massless dark photon with all Standard Model particles is considered. This captures the predictions of a generic model featuring this type of vector boson at sufficiently low energies. In such framework the thermal production rate of dark photons
is computed at leading order, including the contributions of all SM particles. The corresponding cosmological yield of the dark photon and its contribution to the effective number of neutrinos are also calculated. These predictions satisfy the current observational bounds and will be tested by future measurements.
Could compact stars in globular clusters constrain dark matter?
Authors: Garani Raghuveer , Raj Nirmal , Reynoso-Cordova Javier
Published: July 2023

The dark matter content of globular clusters, highly compact gravity-bound stellar systems, is unknown.
It is also generally unknowable, due to their mass-to-light ratios typically ranging between 1-3 in solar units, accommodating a dynamical mass of dark matter at best comparable to the stellar mass.
That said, recent claims in the literature assume densities of dark matter around 1000 GeV/cm3 to set constraints on its capture and annihilation in white dwarfs residing in the globular cluster M4, and to study a number of other effects of dark matter on compact stars.
Motivated by these studies, we use measurements of stellar kinematics and luminosities in M4 to look for a dark matter component via a spherical Jeans analysis; we find no evidence for it, and set the first empirical limits on M4's dark matter distribution.
Our density upper limits, a few × 104 GeV/cm3 at 1 parsec from the center of M4, do not negate the claims (nor confirm them), but do preclude the use of M4 for setting limits on non-annihilating dark matter kinetically heating white dwarfs, which require at least 105 GeV/cm3 densities.
The non-robust nature of globular clusters as dynamical systems, combined with evidence showing that they may originate from molecular gas clouds in the absence of dark matter, make them unsuitable as laboratories to unveil dark matter's microscopic nature in current or planned observations.
Effect of gas mixture pressure on detection sensitivity of molecular iodine in the atmosphere by laser-fluorescent method using a copper vapor laser (578.2 nm)
Authors: Kireev S V , Kondrashov A A , Shnyrev S L , Suganeev S V
Published: July 2023

The paper reports on the calculation studies of the influence of the pressure of the analyzed gas mixture on the measuring sensitivity of the concentrations of 127I2, 127I129I and 129I2 in atmospheric air by the laser-fluorescence method using a copper vapor laser with a wavelength of 578.2 nm as a fluorescence excitation source. It is shown that for each of these iodine molecules there are pressures at which the highest fluorescence intensity is achieved, which correspond to the best detection sensitivity of the molecules. The results obtained can be used in the development of methods for real-time detection of molecular iodine in the atmosphere.
Bidirectional hierarchical quantum teleportation based on an eight-qubit entangled state
Authors: Yang Benchao
Published: July 2023

This article proposes an asymmetric bidirectional hierarchical quantum teleportation protocol, which is based on a quantum channel composed of a maximum of eight-qubit entangled state. With this method, Alice can transmit an unknown single-qubit state to Bob, meanwhile, Bob can transmit an arbitrary unknown two-qubit quantum state to Alice. As a sender with high authority, Bob can send any unknown two-qubit quantum state to Alice only under the sole control of the controller Charlie; Alice, as a sender with low-level permissions, if Bob intends to receive the unknown single-qubit quantum state sent by Alice, he must get the permission and assistance of Charlie and David to complete the communication.
The effect of ambient temperature fluctuations on the output frequency instability of the fiber femtosecond frequency comb
Authors: Filonov A A , Kuznetsov S A , Pivtsov V S , Farnosov S A , Isaeva Y G , Chepurov S V , Koliada N A
Published: July 2023

A study of the influence of temperature fluctuations of individual blocks of a fiber femtosecond frequency comb (FFC) generator and of the entire system as a whole on its output radio frequencies has been carried out. A two-circuit system for thermal stabilization of the air inside the FFC housing was implemented. An additional system for thermal stabilization of the transport fiber, which is included in the measurement scheme (outside the FFC), was implemented. A significant temperature effect on the measured output frequencies of the FFS is shown. Thanks to all the thermal stabilization systems, it has been shown that the instability of the developed fiber FFC introduced into its output microwave frequencies (in addition to the instability of the reference optical standard) is no worse than 2 × 10−16 per 1000 s.
Assessing edge-coupled interdependent network disintegration via rank aggregation and elite enumeration
Authors: Li 李 Yong-Hui 咏徽 , Liu 刘 San-Yang 三阳 , Bai 白 Yi-Guang 艺光
Published: July 2023

The disintegration of networks is a widely researched topic with significant applications in fields such as counter-terrorism and infectious disease control. While the traditional approaches for achieving network disintegration involve identifying critical sets of nodes or edges, limited research has been carried out on edge-based disintegration strategies. We propose a novel algorithm, i.e., a rank aggregation elite enumeration algorithm based on edge-coupled networks (RAEEC), which aims to implement tiling for edge-coupled networks by finding important sets of edges in the network while balancing effectiveness and efficiency. Our algorithm is based on a two-layer edge-coupled network model with one-to-one links, and utilizes three advanced edge importance metrics to rank the edges separately. A comprehensive ranking of edges is obtained using a rank aggregation approach proposed in this study. The top few edges from the ranking set obtained by RAEEC are then used to generate an enumeration set, which is continuously iteratively updated to identify the set of elite attack edges. We conduct extensive experiments on synthetic networks to evaluate the performance of our proposed method, and the results indicate that RAEEC achieves a satisfactory balance between efficiency and effectiveness. Our approach represents a significant contribution to the field of network disintegration, particularly for edge-based strategies.
On the microscopic shell-model version of the Bohr-Mottelson collective model
Authors: Ganev H. G.
Published: July 2023

The recently proposed microscopic shell-model version of the Bohr-Mottelson (BM) collective model is considered in more detail in the coordinate representation. The latter possesses a clear and transparent physical meaning, which reveals several features of the new version of the collective model missed in the previous formulation. The relationship to the original BM model is considered, along with the relationships between the different limiting submodels of the microscopic version of the BM model, which closely resemble the relationships of the original Wilets-Jean and rotor models. The kinematically correct many-particle wave functions of the microscopic version of the BM model, conserving the experimentally observed integrals of motion, are shown to consist of collective irrotational-flow and intrinsic components

in accordance with the original BM unified model. The general BM Hamiltonian is obtained as a contraction limit of the microscopic many-particle nuclear Hamiltonian, or, alternatively, by restricting the latter to the scalar

irreducible collective space.
Spatially repeatable components from ultrafast ultrasound are associated with motor unit activity in human isometric contractions
*
Authors: Rohlén Robin , Carbonaro Marco , Cerone Giacinto L , Meiburger Kristen M , Botter Alberto , Grönlund Christer
Published: July 2023

Objective. Ultrafast ultrasound (UUS) imaging has been used to detect intramuscular mechanical dynamics associated with single motor units (MUs). Detecting MUs from ultrasound sequences requires decomposing a velocity field into components, each consisting of an image and a signal. These components can be associated with putative MU activity or spurious movements (noise). The differentiation between putative MUs and noise has been accomplished by comparing the signals with MU firings obtained from needle electromyography (EMG). Here, we examined whether the repeatability of the images over brief time intervals can serve as a criterion for distinguishing putative MUs from noise in low-force isometric contractions. Approach. UUS images and high-density surface EMG (HDsEMG) were recorded simultaneously from 99 MUs in the biceps brachii of five healthy subjects. The MUs identified through HDsEMG decomposition were used as a reference to assess the outcomes of the ultrasound-based components. For each contraction, velocity sequences from the same eight-second ultrasound recording were separated into consecutive two-second epochs and decomposed. To evaluate the repeatability of components’ images across epochs, we calculated the Jaccard similarity coefficient (JSC). JSC compares the similarity between two images providing values between 0 and 1. Finally, the association between the components and the MUs from HDsEMG was assessed. Main results. All the MU-matched components had JSC > 0.38, indicating they were repeatable and accounted for about one-third of the HDsEMG-detected MUs (1.8 ± 1.6 matches over 4.9 ± 1.8 MUs). The repeatable components (JSC > 0.38) represented 14% of the total components (6.5 ± 3.3 components). These findings align with our hypothesis that intra-sequence repeatability can differentiate putative MUs from noise and can be used for data reduction. Significance. This study provides the foundation for developing stand-alone methods to identify MU in UUS sequences and towards real-time imaging of MUs. These methods are relevant for studying muscle neuromechanics and designing novel neural interfaces.
The effect of gas injection location on a lithium vapor box divertor in NSTX-U
Authors: Emdee E.D. , Goldston R.J.
Published: July 2023

The lithium vapor box divertor is a proposed divertor design that will minimize contamination of the upstream plasma in a fusion device, while also ensuring protection of the target. In this design lithium is evaporated near the target by high temperature lithium surfaces, dissipating the plasma heat flux. The lithium vapor box has been predicted via the fluid-kinetic code scrape off layer plasma simulator (SOLPS-ITER) to achieve low (

n

L
i

/

n

e

∼
 

0.05) upstream concentrations of lithium and low target heat fluxes. Here we compare two choices of deuterium gas puff location using SOLPS-ITER, the private flux region (PFR) and the common flux region (CFR), and find significant differences in the contamination level required to reach an acceptable target heat flux (defined here as q

tar

max

⩽

10 MW m−2). Deuterium gas puffing from the PFR is seen to better reduce upstream lithium contamination. The difference in puffing location is seen to cause changes in the upstream flow of lithium ions. The PFR puff, having better access to the separatrix, can better reduce the upstream-directed flow of lithium near the separatrix which is the primary source of contamination due to a large thermal force in this region. Puffing from the CFR, partially due to inefficacy at reducing separatrix lithium flow, has higher lithium concentration within the plasma. Solutions that reduce the heat flux to below 10 MW m−2 have a range of lithium concentrations between

n

L
i

/

n

e

 
∼
 

0.01–0.12 depending on puff intensity, location, evaporator temperature and recycling at the various plasma facing components. The efficacy of the puffs is tested for sensitivity to deuterium recycling coefficient at the target, evaporators, and main chamber walls. A CFR located puff is found to be more dependent on the recycling coefficients used than a PFR located puff. regardless of the set of recycling coefficients chosen, PFR puffing achieves lower lithium contamination than CFR puffing for a given heat flux.
Simulation-based Fatigue Life Analysis of Polyimide Film in Afterburner Fuel Distributor
Authors: Ban Jinlei , Zhao Zhihui , Huang Sen , Han Yongjian , Zhou Zhenhua , Wang Fei , Zhou Weixuan
Published: July 2023

Aiming at the problem of premature failure of organic material polyimide film in the afterburner fuel distributor of a turbofan engine, the material parameters of polyimide film and the temperature and the fluctuation amplitude of the film during use were obtained based on previous investigation. The finite element simulation model of polyimide film was established in ANSYS software to study the Mises stress distribution and weak area distribution of the film when the film fails in the form of fracture. Based on the fatigue life calculation theory of probabilistic fracture mechanics, the fatigue life cycle times and their variation rules of the film under different reliability were obtained. The results show that there is stress concentration in the film, and the stress con-centration and weak area of the film occur at the outer edge of the film clamping. The fatigue life cycle times of the film under different reliability are calculated, and the fatigue life cycle times decrease with the increase of reliability.
Computational Fluid Dynamics of Useful Grinding Fluid Flow and Sensitivity Analysis of Grinding Parameters
Authors: Sharma Vivek , Ghosh Amitava
Published: July 2023

In the grinding process, a high speed rotating grinding wheel develops a stiff air barrier around it. This air barrier restricts the flow of incoming grinding fluid through a nozzle jet into the grinding zone, and this leads to a considerable amount of grinding fluid being wasted. An insufficient amount of grinding fluid from the nozzle jet not reaching the grinding wheel-workpiece contact zone will result in many defects in the workpiece as well as in the grinding wheel. In this paper, a unique method of air scraper is modelled and simulated in order to impinge the grinding fluid maximum through a thick boundary layer around the periphery of the rotating grinding wheel and the effect of grinding parameters are analyzed and Ugff rate equation established using Box Behnken Design method.
QFD/TRIZ Based Mechanical Structure Design of Elderly Walker
Authors: Wang Zongsheng , Zhang Baoyi
Published: July 2023

To ensure the safety of the elderly and to provide a convenient and comfortable travel experience, elderly walkers are widely used. The Quality Function Deployment (QFD)/Teoriya Resheniya Izobretatelskikh Zadatch (TRIZ) integrated model is constructed and the specific implementation process is given by starting from the mechanical structure of the product. Firstly, the design requirements of the existing structure of the product are obtained from the elderly users by interview, and the requirements are classified into three categories: walking state, stationary state, and handling state from the state of the elderly travel. Then, on the basis of the requirements, a characteristic House of Quality (HOQ) for walkers suitable for the elderly was constructed, and the relationship matrix inside the HOQ was further analyzed to integrate and eliminate the characteristics of different products. Finally, the negative correlation characteristic problem in the autocorrelation matrix of the quality roof is extracted, and after transforming it into TRIZ problem, the product characteristic conflict in the design stage is eliminated by using TRIZ theory. Through the combination of the two methods, the objective requirement acquisition and the scientific design positioning in the design research stage are ensured. This study verifies the feasibility of the integrated model applied to elderly walkers through specific design practices.
Design of a New Bulletproof Structure and Simulation of Stiffness and Strength of the Whole Shelter
Authors: Wang Shengdong , Shen Yanyou , Zhou Chi
Published: July 2023

In order to improve the battlefield survivability of military equipment and personnel, more and more research institutions have conducted research on the bulletproof performance of equipment. This paper analyzes the advantages and disadvantages of several main bulletproof materials and their applicable environments, and briefly analyzes the damage performance of typical antiradiation missile warhead fragments. On this basis, a new type of hanging bullet proof structure is designed, which can be used to protect the warhead fragments of anti radiation missile. Using ANSYS simulation software, the stiffness and strength of the whole cabin under hoisting conditions are simulated.
Development and Validation of an in-House Direct Simulation Monte Carlo Code for Supersonic Rarefied Gas Microflows
Authors: Hew J K J , Boswell R W
Published: July 2023

An in-house Direct Simulation Monte Carlo (DSMC) code has been developed using an object-oriented interface for the purpose of eventually modelling gas and plasma microflows in micromechanical systems, by coupling it with an existing Particle-In-Cell (PIC) solver. The code is validated with canonical flow problems such as the micro-Couette and micro-Poiseuille flows. Since the emphasis is on supersonic and highly compressible flows, we perform validation studies of our algorithm for high velocity and Mach number cases, as compared to known analytical or semi-analytical profiles via asymptotic Bhatnagar-Gross-Krook (BGK) and Chapman-Enskog theory. Reasonably good agreement is found for all the test cases, which indicates the reliability of the present algorithm for modelling supersonic rarefied gas flows. Our results have implications for future validation studies of DSMC codes, where concrete quantitative theoretical and experimental comparisons across different flow configurations are required.
Experimental Investigation of Novel Liquid Flow Measurement by Using Thermoelectric Module
Authors: Oncha-ek P , Prasongsil C , Saitong N , Saimala W , Rungruang C , Leephakpreeda T
Published: July 2023

This paper presents an experimental investigation of liquid flow measurement by using a thermoelectric module. The measuring principle is based on the Seebeck effect of the thermoelectric module and the energy balance of convective heat transfer between the liquid flow and the thermoelectric module during implementation. The experimental studies confirm the viability of the thermoelectric module in determining the flow rates of water. In experiments, the results show that the determined flow rates by using the thermoelectric module are close to the actual flow rates of water with a coefficient of determination R2 of 0.9965. In addition to the straightforward measuring principle, low-cost material, no limitation of fluid types as well as directions of flows in a pipe, and no requirement of electrical power source make the thermoelectric module noteworthy as a sensor material in developing liquid flow meters.
AI Intelligent Detection Technology of Metal Hose for Rocket Engine
Authors: Chen Chong Kun
Published: July 2023

Endoscope is an important method for defect detection of metal hose used in rocket engine. Due to the traditional endoscopic detection technology is dependent on manual and low detection efficiency, this paper introduces Ai Image recognition technology to detect inner surface defects of metal hose. Aiming at the problem that most of the defects on the inner wall of the bellows of metal hose are small in scale and easy to be misjudged, a method of post-processing and rechecking of the bellows defect detection model is proposed, it is used to strengthen the defect detection model of the inner wall of the bellows of the metal hose for rocket engine. In this paper, based on the block classification network, the defect detection of the captured image of bellows is carried out, and the defect detection results of n*n blocks are output, then the metal hose defects are classified by using the bi fine-grained classification network with small structure, and the final n*n multi-class detection results are obtained. The results show that the engine and model of Ai Algorithm reduce the rate of missed detection and false detection, and improve the reliability of endoscope detection.
Analysis of an Abnormal Secondary Voltage Accident of Capacitive Voltage Transformer
Authors: Ouyang Zeyu , Chen Jiasheng , Zhu Silin , Dai Jiyulei
Published: July 2023

Capacitive Voltage Transformer (CVT) is an important measurement and protection equipment in power system, which has the characteristics of high electrical strength, large insulation margin and reliable operation. During the operation of CVT, its upper and lower capacitors, compensation reactors, lightning rods and other components often have faults. The faults of CVT can be found in time by judging the secondary voltage value. In this paper, an abnormal secondary voltage fault of CVT is introduced. Combined with test and disassembly analysis, it is determined that the fault is caused by breakdown of capacitor unit. Through fault simulation, this paper studies the typical CVT faults and the change law of secondary voltage, and puts forward the threshold of the secondary voltage abnormal alarm of CVT, providing important reference for CVT online monitoring.
Design and Analysis of a Vertical Electric Ducted Fan for Unmanned Aerial Vehicles
Authors: Shiau Y R , Fang J , Huang Y C
Published: July 2023

Several types of multirotor unmanned aerial vehicles (UAVs) are widely used in various industrial activities. UAVs with electric ducted fans (EDFs) have been developed to mitigate the risks associated with rotary blades, which are installed on the exterior structure of conventional UAVs and exposed to the ambient environment. Particularly, vertical EDFs have become a focus in the field of UAV design because they require less space for the flow channel compared with horizontal EDFs. In this study, a vertical EDF UAV model was developed. Structural and flow field analysis was performed in Ansys software to determine the optimal design configuration. The results confirmed that the designed model facilitated smooth air flow with favorable inlet and outlet velocity. The vehicle structure required minor adjustment to reduce the frequency of occurrence of vortices. Overall, this study made two research contributions. First, an EDF UAV model was developed to mitigate the risk of rotary blades being exposed to the ambient environment. Second, a vertical EDF system was proposed to reduce the flow channel space and maintain the outlet velocity, thereby improving the takeoff, landing, and thrust performance of UAVs.
Application of Impact Elastic Wave Method in Nondestructive Testing Technology
Authors: Feng Shaojie , Liu Chaoran
Published: July 2023

This paper summarizes the research status of nondestructive testing technology of building structures, focuses on the technical principles and characteristics of the first wave phase inversion method and the impact elastic wave method, and on this basis, the nondestructive detector based on the first wave phase reversal and impact elastic wave were used to conduct experimental research on cracks, materials, defects and thickness of the test block. The results show that the first wave phase inversion has low requirements for the test environment, and the test results are affected by the water, dust, steel reinforcement and signal attenuation inside the crack, which have a tendency to be shallow compared with the actual value. The first wave of defect location, size and other results are consistent with the actual situation, which verifies the good reliability of the nondestructive testing technology based on impact elastic wave.
A large area 100-channel PICOSEC Micromegas detector with time resolution at the 20 ps level
Authors: Utrobicic A. , Angelis Y. , Bortfeldt J. , Brunbauer F. , Chatzianagnostou E. , Dehmelt K. , Fanourakis G. , Floethner K.J. , Gallinaro M. , Garcia F. , Garg P. , Giomataris I. , Gnanvo K. , Gustavsson T. , Iguaz F.J. , Janssens D. , Kallitsopoulou A. , Kovacic M. , Legou P. , Lisowska M. , Liu J. , Lupberger M. , Maniatis I. , Meng Y. , Muller H. , Oliveri E. , Orlandini G. , Papaevangelou T. , Pomorski M. , Ropelewski L. , Sampsonidis D. , Scharenberg L. , Schneider T. , Sohl L. , van Stenis M. , Tsipolitis Y. , Tzamarias S.E. , Veenhof R. , Wang X. , White S. , Zhang Z. , Zhou Y.
Published: July 2023

The PICOSEC Micromegas precise timing detector is based on a Cherenkov radiator coupled to a photocathode operating in a semi-transparent mode and a Micromegas amplification structure. The first proof of concept single-channel prototype was able to achieve a time resolution below 25 ps. One of the crucial aspects in the development of precise timing gaseous detectors applicable in high-energy physics experiments is a modular design that enables large area coverage. The first 19-channel multi-pad prototype with an active area of approximately 10 cm2suffered from degraded timing resolution due to the non-uniformity of the preamplification gap thickness. A new 100 cm2detector module with 100 channels based on a rigid hybrid ceramic/FR4 Micromegas board for improved drift gap uniformity was developed. Initial measurements with 80 GeV/c muons showed improvements in timing response over the measured pads and a time resolution below 25 ps. More recent measurements with a thinner drift gap detector module and newly developed RF pulse amplifiers show that the pad centre resolution can be enhanced to the level of 17 ps. This work will present the development of the detector from structural simulations, design, and beam test commissioning with a focus on the timing performance of a thinner drift gap detector module in combination with new electronics using an automated timing scan method.
TiO2 nanotubes promote osteogenic differentiation of human bone marrow stem cells via epigenetic regulation of RMRP/DLEU2/EZH2 pathway
Authors: Li Shuangqin , Deng Qing , Si Qiqi , Li JinSheng , Zeng Huanghe , Chen Song , Guo Tailin
Published: July 2023

TiO2 nanotubes (TNTs) significantly promote osteogenic differentiation and bone regeneration of cells. Nevertheless, the biological processes by which they promote osteogenesis are currently poorly understood. Long non-coding RNAs (lncRNAs) are essential for controlling osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Epigenetic chromatin modification is one of the pathways in which lncRNAs regulate osteogenic differentiation. Here, we reported that TNTs could upregulate lncRNA RMRP, and inhibition of lncRNA RMRP in human BMSCs (hBMSCs) grown on TNTs could decrease runt-related transcription factor 2 (RUNX2), alkaline phosphatase, osteopontin, and osteocalcin (OCN) expression. Furthermore, we discovered that inhibiting lncRNA RMRP elevated the expression of lncRNA DLEU2, and lncRNA DLEU2 knockdown promoted osteogenic differentiation in hBMSCs. RNA immunoprecipitation experiments showed that lncRNA DLEU2 could interact with EZH2 to induce H3K27 methylation in the promoter regions of RUNX2 and OCN, suppressing gene expression epigenetically. According to these results, lncRNA RMRP is upregulated by TNTs to promote osteogenic differentiation through DLEU2/EZH2-mediated epigenetic modifications.
Wigner function dynamics with boundaries expressed as convolution
Authors: Seidov S S
Published: July 2023

In the present paper a method of finding the dynamics of the Wigner function of a particle in an infinite quantum well is developed. Starting with the problem of a reflection from an impenetrable wall, the obtained solution is then generalized to the case of a particle confined in an infinite well in arbitrary dimensions. It is known, that boundary value problems in the phase space formulation of the quantum mechanics are surprisingly tricky. The complications arise from nonlocality of the expression involved in calculation of the Wigner function. Several ways of treating such problems were proposed. They are rather complicated and even exotic, involving, for example, corrections to the kinetic energy proportional to the derivatives of the Dirac delta–function. The presented in the manuscript approach is simpler both from analytical point of view and regarding numerical calculation. The solution is brought to a form of convolution of the free particle solution with some function, defined by the shape of the well. This procedure requires calculation of an integral, which can be done by developed analytical and numerical methods.
Rotational vector-based analysis of turbulent structures in channel flow using large eddy simulation simulation
Authors: Zhang Shen , Gui Nan , Yang Xingtuan , Tu Jiyuan , Jiang Shengyao
Published: July 2023

Even with modern measurement techniques and data from direct numerical simulation (DNS), it is very difficult to identify the individual attached eddies and understand their dynamical behavior due to the multi-scale nature of the eddies in wall-bounded flows, which puts these issues at the center of the current debate. However, Liutex vector (
L
for short), a rotational vector field with information on both the rotation axis and swirling strength, has recently been developed by Prof. Liu’s group as a more accurate and clear definition of a vortex. Combining conventional and
L
methods may provide more detailed information about the complex flow structures as well as insights into the flow’s mixing and transport features. We simulated the channel flow in large eddy simulation by implementing an inflow condition based on the box turbulence. After validating the results with DNS data, we used
L
isosurfaces and their vector profiles to track ordered flow structures in wall-bounded turbulence. Based on the data, we observe numerous turbulent phenomena that have been described in other works with different visualization techniques. Moreover, the shear contamination on the wall is the most severe while all the root-mean-square
L
component variations are negligible. Due to the presence of background shear, the peak location of vorticity fluctuation is closer to the wall than the corresponding
L
fluctuation, and the displacement of peak location brought on by shear contamination is greatest for the spanwise component (z-component) of the vorticity fluctuation. According to the two-point correlation of
L
components, the streamwise size of turbulent structures does not vary considerably with

y
+

, however, the spanwise size of turbulent structures increases gradually as

y
+

increases.
Synthesis and characterization of wood-based phase change material with high photothermal conversion efficiency
Authors: Weng Lu , Lin Xianxian , Chen Xinyu , Liu Pengwei , Zhu Zezheng , Chen Yulian , Qiu Chendong , Lu Tonghua , Wei Renzhong , Zhang Yi , Sun Weisheng , Guo Xi
Published: July 2023

Phase change materials attract tremendous interest for building energy conservation due to their auto-temperature regulation and thermal energy storage capacity. However, its practical application is hindered due to the leakage problem and poor photothermal conversion efficiency. To address these issues, a scalable wood-based phase change material was prepared by impregnating polyethylene glycol (PEG) into wood particles doped with Fe3O4 and subsequent a hot press in this study. PEG was encapsulated by wood particles through its abundant pore structure and leakage rate of prepared wood-based phase change material (FWPCM) was only 2.9%, which solved the leakage problem effectively. FWPCM presented high latent heat of 73 J g−1 and slowed down the temperature change obviously. Addition of Fe3O4 powder endowed FWPCM a high photothermal conversion efficiency and thermal conductivity (0.3545 W/(m*K) was increased by 125% compared to PW. So FWPCM had potential to be used as building engineering material for energy collecting, storage and conversion benefited by its great thermal performance, superior durability, simple preparing process and acceptable mechanical property.
Gradient self-organized dislocation in expanded austenite layer during low-temperature nitriding
Authors: Che H L , Yang X , Liu H Y , Lei M K
Published: July 2023

A typical nitrogen expanded austenite layer is formed by plasma-based low-energy nitrogen ion implantation (PBLEII) on AISI 304L austenitic stainless steel at a moderate temperature of 380 °C. The dislocation self-organization structure in the nitrogen expanded austenite layer is characterized as an evolution from partial and Lomer-Cottrell dislocations in the inner layer near the interface to multilayer stacking faults in the outer nitrided layer. The self-organized dislocation density and forms are essentially dependent on the plastic deformation, strain-gradient, and nitrogen-related stacking fault energies, respectively, due to the constrained expansion in the nitrided layer. As the nitrogen concentration in the austenitic matrix increases, the stacking fault energy gradually decreases, resulting in the transformation of the defect from Lamer-Cottrell dislocations to multilayer stacking faults. The appropriate stress, which is associated with orderly stress relief during dislocation self-organization, preserves the integrity of the nitrided layer with a combinedly improved in wear and corrosion resistance. Nitriding-induced dislocation self-organization is basically explored as the formation mechanism of the nitrogen expanded austenite layer, contributing to the development of the specific low-temperature nitriding austenitic steel.
Efficient measurement schemes for bosonic systems
Authors: Gu Tianren , Yuan Xiao , Wu Bujiao
Published: July 2023

Boson is one of the most basic types of particles and preserves the commutation relation. An efficient way to measure a bosonic system is important not only for simulating complex physics phenomena of bosons (such as nuclei) on a qubit based quantum computer, but for extracting classical information from a quantum simulator/computer that itself is built with bosons (such as a continuous variable quantum computer). Extending the recently proposed measurement schemes for qubits, such as shadow tomography and other local measurement schemes, here we study efficient measurement approaches for bosonic systems. We consider truncated qudit and continuous variable systems, corresponding to simulated bosons on a discrete quantum computer and an inherent boson system, respectively, and propose different measurement schemes with theoretical analyses of the variances for these two cases. We numerically test the schemes for measuring nuclei vibrations simulated using a discrete quantum computer and a continuous variable Gaussian state, and the simulation results show great improvement of the performance of the proposed method compared to conventional ones.
Contrail radiative dependence on ice particle number concentration
Authors: De León Rubén Rodríguez , Lee David S
Published: July 2023

Recent studies on low aromatic fuels have shown that lower soot number emissions may reduce contrail ice particle number concentrations (N
ice). Here we implemented, in a sophisticated radiative transfer model, two ice particle size distribution schemes in order to estimate the contrail radiative forcing’s (RFs) dependence on these prospective N
ice reductions resulting from the introduction of sustainable aviation fuels. The results show that an 85% contrail N
ice reduction produces a 35% smaller contrail RF, while neglecting all non-radiative effects. This estimate of an RF reduction only considers the effects of the N
ice change assumed here, and neglects other potentially important microphysical mechanisms that may change the relationship between soot number emissions and N
ice. A comparison of our results with previous published estimates from full climate model simulations, shows similar RF reductions to those which also take into account non-radiative mechanisms, evidencing the need for more studies in order to allocate the contribution from radiative and non-radiative changes, as this would guide possible mitigation implementations. Despite these modeled contrail RF reductions being largely independent of the assumed ice water content (IWC), it is only through simultaneous improvement of the IWC and N
ice representation in models that contrail RF estimates can be better constrained. This is because our calculated RF varied by a factor of 3 when assuming a ±30% IWC range; and by a factor of 5 if a, still conservative, ±60% IWC range was prescribed, suggesting that the differences in the prescribed IWC and N
ice values in different models may explain the large discrepancies amongst published RF estimates. Recent estimates of higher N
ice values, and lower IWCs found in contrails even after several hours, compared to surrounding cirrus under similar atmospheric conditions, were assessed to conclude that it is mainly the differences in IWC that make young contrails have a smaller RF, and to reduce our previous estimate for linear contrail RF for year 2006 by 65%.
The heterotic 𝐺₂ system on contact Calabi–Yau 7-manifolds
Authors: Lotay Jason , Sá Earp Henrique
Published: July 2023

We obtain non-trivial approximate solutions to the heterotic

G

2

\mathrm {G}_2

system on the total spaces of non-trivial circle bundles over Calabi–Yau

3
3

-orbifolds, which satisfy the equations up to an arbitrarily small error, by adjusting the size of the

S
1

S^1

fibres in proportion to a power of the string constant

α
′

\alpha ’

. Each approximate solution provides a cocalibrated

G

2

\mathrm {G}_2

-structure, the torsion of which realises a non-trivial scalar field, a constant (trivial) dilaton field and an

H
H

-flux with non-trivial Chern–Simons defect. The approximate solutions also include a connection on the tangent bundle which, together with a non-flat

G

2

\mathrm {G}_2

-instanton induced from the horizontal Calabi–Yau metric, satisfy the anomaly-free condition, also known as the heterotic Bianchi identity. The approximate solutions fail to be genuine solutions solely because the connections on the tangent bundle are only

G

2

\mathrm {G}_2

-instantons up to higher order corrections in

α
′

\alpha ’

.
On categories 𝒪 of quiver varieties overlying the bouquet graphs
Authors: Tsvelikhovskiy Boris
Published: July 2023

We study representation theory of quantizations of Nakajima quiver varieties associated to bouquet quivers. We show that there are no finite dimensional representations of the quantizations

A

¯

λ

(
n
,
ℓ
)

\overline {\mathcal {A}}_{\lambda }(n, \ell )

if both

dim
⁡
V
=
n

\operatorname {dim}V=n

and the number of loops

ℓ
\ell

are greater than

1
1

. We show that when

n
≤
3

n\leq 3

there is a Hamiltonian torus action with finitely many fixed points, provide the dimensions of Hom-spaces between standard objects in category

O

\mathcal {O}

and compute the multiplicities of simples in standards for

n
=
2

n=2

in case of one-dimensional framing and generic one-parameter subgroups. We establish the abelian localization theorem and find the values of parameters, for which the quantizations have infinite homological dimension.
The zeros of even period polynomials for newforms on Γ₀(𝑁)
Authors: Choi SoYoung
Published: July 2023

We prove that for even integer

k
≥

k
0

k\geq k_0

, almost all of zeros of the even period polynomial associated to a newform of weight

k
k

on

Γ
0

(
N
)

\Gamma _0(N)

are on the circle

|

z

|

=
1

/

N

|z|=1/\sqrt {N}

.
Secondary homological stability for unordered configuration spaces
Authors: Himes Zachary
Published: July 2023

Secondary homological stability is a recently discovered stability pattern for a sequence of spaces exhibiting homological stability and it holds outside the range where the homology stabilizes. We prove secondary homological stability for the homology of the unordered configuration spaces of a connected manifold. The main difficulty is the case that the manifold is closed because there are no obvious maps inducing stability and the homology eventually is periodic instead of stable. We resolve this issue by constructing a new chain-level stabilization map for configuration spaces.
Barriers and Facilitators to Gender-affirming Hormone Therapy in the Veterans Health Administration
Authors: Wolfe Hill L , Boyer Taylor L , Shipherd Jillian C , Kauth Michael R , Jasuja Guneet K , Blosnich John R
Published: July 2023

Background

In 2011, the Veterans Health Administration (VHA) established a policy for the delivery of transition-related services, including gender-affirming hormone therapy (GAHT), for transgender and gender diverse (TGD) patients. In the decade since this policy’s implementation, limited research has investigated barriers and facilitators of VHA’s provision of this evidence-based therapy that can improve life satisfaction among TGD patients.

Purpose

This study provides a qualitative summary of barriers and facilitators to GAHT at the individual (e.g., knowledge, coping mechanisms), interpersonal (e.g., interactions with other individuals or groups), and structural (e.g., gender norms, policies) levels.

Methods

Transgender and gender diverse patients (n = 30) and VHA healthcare providers (n = 22) completed semi-structured, in-depth interviews in 2019 regarding barriers and facilitators to GAHT access and recommendations for overcoming perceived barriers. Two analysts used content analysis to code and analyze transcribed interview data and employed the Sexual and Gender Minority Health Disparities Research Framework to organize themes into multiple levels.

Results

Facilitators included having GAHT offered through primary care or TGD specialty clinics and knowledgeable providers, with patients adding supportive social networks and self-advocacy. Several barriers were identified, including a lack of providers trained or willing to prescribe GAHT, patient dissatisfaction with prescribing practices, and anticipated or enacted stigma. To overcome barriers, participants recommended increasing provider capacity, providing opportunities for continual education, and enhancing communication around VHA policy and training.

Conclusions

Multi-level system improvements within and outside the VHA are needed to ensure equitable and efficient access to GAHT.