bluuebunny/crossref_metadata_2025 huggingface dataset:
Convective scale and subadiabatic layers in simulations of rotating compressible convection
Authors: Käpylä P. J.
Published: January 2024

Context. Rotation is thought to influence the size of convective eddies and the efficiency of convective energy transport in the deep convection zones of stars. Rotationally constrained convection has been invoked to explain the lack of large-scale power in observations of solar flows.

Aims. Our main aims are to quantify the effects of rotation on the scale of convective eddies and velocity as well as the depths of convective overshoot and subadiabatic Deardorff layers.

Methods. We ran moderately turbulent three-dimensional hydrodynamic simulations of rotating convection in local Cartesian domains. The rotation rate and luminosity of the simulations were varied in order to probe the dependency of the results on Coriolis, Mach, and Richardson numbers measuring the influences of rotation, compressibility, and stiffness of the radiative layer. The results were compared with theoretical scaling results that assume a balance between Coriolis, inertial, and buoyancy (Archimedean) forces, also referred to as the CIA balance.

Results. The horizontal scale of convective eddies decreases as rotation increases, and it ultimately reaches a rotationally constrained regime consistent with the CIA balance. Using a new measure of the rotational influence on the system, we found that even the deep parts of the solar convection zone are not in the rotationally constrained regime. The simulations captured the slowly and rapidly rotating scaling laws predicted by theory, and the Sun appears to be in between these two regimes. Both the overshooting depth and the extent of the Deardorff layer decrease as rotation becomes more rapid. For sufficiently rapid rotation, the Deardorff layer is absent due to the symmetrisation of upflows and downflows. However, for the most rapidly rotating cases, the overshooting increases again due to unrealistically large Richardson numbers that allow convective columns to penetrate deep into the radiative layer.

Conclusions. Relating the simulations with the Sun suggests that the convective scale, even in the deep parts of the Sun, is only mildly affected by rotation and that some other mechanism is needed to explain the lack of strong large-scale flows in the Sun. Taking the current results at face value, the overshoot and Deardorff layers are estimated to span roughly 5% of the pressure scale height at the base of the convection zone in the Sun.
Aligned fractures on asteroid Ryugu as an indicator of thermal fracturing
Authors: Schirner L. , Otto K. A. , Delbo M. , Matz K.-D. , Sasaki S. , Sugita S.
Published: January 2024

Context. Asteroid and comet surfaces are exposed to a complex environment that includes low gravity, high temperature gradients, and a bombardment of micrometeorites and cosmic rays. Surface material exposed to this environment evolves in a specific way depending on various factors such as the bodies’ size, heliocentric distance, and composition. Fractures in boulders, as seen on asteroid Ryugu, can help to determine and constrain the dominant processes eroding small-body surface materials. It is also possible to estimate fracture growth timescales based on the abundance and length of fractures in boulders.

Aims. We analyse the number, orientation, and length of fractures on asteroid Ryugu to establish the relation between the fractures and the processes that may have formed them. We also compare our results to similar investigations conducted on other small bodies and estimate the timescale of fracture growth.

Methods. 198 high-resolution Hayabusa2 images of asteroid Ryugu suitable for our fracture analysis were selected and map-projected. Within these images, fractures in boulders were manually mapped using the QGIS software. The fracture coordinates were extracted and the fractures’ orientation and length were computed for 1521 identified fractures.

Results. Fractures in boulders on asteroid Ryugu are found to be preferentially north-south aligned, suggesting a formation through thermal erosion. Modeling the fracture length indicates a fracture growth timescale of 30 000 to 40 000 yr, slightly younger than ages found previously for asteroid Bennu. The errors in these ages, due to uncertainties about the thermophysical parameters used in this model, are substantial (−33 000 yr +250 000 yr). However, even with these large errors, the model suggests that thermal fracturing is a geologically fast process. These times are not too dissimilar to those quoted in the literature for Ryugu and Bennu, since similar thermophysical material parameters for Ryugu and Bennu seem likely.
Galaxy clustering multi-scale emulation
Authors: Dumerchat Tyann , Bautista Julian
Published: January 2024

Simulation-based inference has seen increasing interest in the past few years as a promising approach to modelling the non-linear scales of galaxy clustering. The common approach, using the Gaussian process, is to train an emulator over the cosmological and galaxy–halo connection parameters independently for every scale. We present a new Gaussian process model that allows the user to extend the input parameter space dimensions and to use a non-diagonal noise covariance matrix. We use our new framework to simultaneously emulate every scale of the non-linear clustering of galaxies in redshift space from the ABACUSSUMMITN-body simulations at redshift z = 0.2. The model includes nine cosmological parameters, five halo occupation distribution (HOD) parameters, and one scale dimension. Accounting for the limited resolution of the simulations, we train our emulator on scales from 0.3 h−1 Mpc to 60 h−1 Mpc and compare its performance with the standard approach of building one independent emulator for each scale. The new model yields more accurate and precise constraints on cosmological parameters compared to the standard approach. As our new model is able to interpolate over the scale space, we are also able to account for the Alcock-Paczynski distortion effect, leading to more accurate constraints on the cosmological parameters.
Unveiling the intricate symphony of nonlinear pulsation mode interactions in high-amplitudeδScuti stars
Authors: Niu Jia-Shu , Xue Hui-Fang
Published: January 2024

Information on the interiors of stars can be gleaned from their pulsations. Pulsation modes, which are determined by the internal state and structure of a star, are typically considered stable over short timescales. These independent pulsation modes have been used in asteroseismology to determine the interior structures of stars. Here, we report the discovery of peculiar pulsation mode interactions in the high-amplitudeδScuti star KIC 6382916 (J19480292+4146558) that challenge the reliability of independent pulsation modes as indicators of a star’s internal structure. Through analysis of archival data, we find distinct variations in the amplitudes and frequencies of three independent pulsation modes and their harmonics and combinations over approximately 20 days. These variations can reach amplitudes of about 140% and frequency variations of about 12%. Correlation analysis of amplitude and frequency variations reveal additional pulsation mode interaction details and patterns. Notably, our findings regarding the phenomena related to the harmonics of independent pulsation modes challenge the traditional understanding in this area. These discoveries serve as cornerstones for future research and advance nonlinear asteroseismology.
Doubly substituted isotopologues of HCCCN in TMC-1: Detection of D13CCCN, DC13CCN, DCC13CN, DCCC15N, H13C13CCN, H13CC13CN, HC13C13CN, HCC13C15N, and HC13CC15N
Authors: Tercero B. , Marcelino N. , Roueff E. , Agúndez M. , Cabezas C. , Fuentetaja R. , de Vicente P. , Cernicharo J.
Published: January 2024

We report the first detection in space of a complete sample of nine doubly substituted isotopologues of HCCCN towards the cyanopolyyne peak of TMC-1 using observations of the QUIJOTE1 line survey taken with the Yebes 40 m telescope. We detected D13CCCN, DC13CCN, DCC13CN, DCCC15N, H13C13CCN, H13CC13CN, HC13C13CN, HCC13C15N, and HC13CC15N through their J = 4 − 3 and J = 5 − 4 lines in the 7 mm window. In addition, we present an extensive analysis of the emission of HCCCN and its singly substituted isotopologues through a large velocity gradient model of the lines detected at 7 mm and 3 mm using the Yebes 40 m and the IRAM 30 m telescopes, respectively. The derived column densities for all the isotopologues are consistent in the two spectral bands for an H2 volume density of 1 × 104 cm−3 and a kinetic temperature of 10 K. Whereas we observed a 13C fractionation for HCC13CN and other double isotopologues with a 13C atom adjacent to the nitrogen atom, we derived similar C/13C abundance ratios for the three 13C substituted species of DCCCN. This suggests additional chemical discrimination for deuterated isotopologues of HCCCN. Finally, we present the spatial distribution of the J = 4 − 3 and J = 5 − 4 lines from the singly substituted species observed with the Yebes 40 m telescope. The emission peak of the spatial distribution of DCCCN appears to be displaced by ∼40″ with respect to that of HCCCN and the 13C and 15N isotopologues. In addition to a different formation route for the deuterated species, we could also expect that this differentiation owing to the deuterium fractionation is more efficient at low temperatures, and therefore, that deuterated species trace a colder region of the cloud.
Online sales prediction approach using methodology of CRISP-DM
Authors: Wang Chunyang , Stupina Alena , Bezhitskiy Sergey
Published: January 2024

This article studies the sales forecasting problem in the field of e-commerce. Based on the CRISP-DM methodology, innovative data mining technology is used to construct a variety of forecasting models, and is compared and optimized. This article improves the quality and quantity of sales forecasts and provides enterprises with more accurate and effective decision support. In terms of modeling optimization in this article, data mining models such as random forest, support vector machine, and neural network are used for comprehensive prediction, and comparative analysis is conducted with the classic multiple linear regression model. Through model evaluation and optimization, this paper achieved better prediction performance and accuracy. This research has certain theoretical significance and practical value, and provides new ideas and methods for the marketing decisions and business development of e-commerce enterprises.
Process management of heterogeneous services in a digital university based on modified GERT networks
Authors: Korpacheva Larisa , Fedorova Alexandra , Makienko Danila , Novoshinskiy Stanislav
Published: January 2024

The research is devoted to the issues of managing the processes of the information and computing environment in a digital university, which have a distributed, heterogeneous, probabilistic, poorly controlled nature. To improve the efficiency of managing the processes in a digital university, the authors of the research analyzed scientific papers in the field of the information technology infrastructure of organizational and economic systems and universities, formulated the basic principles of information technology infrastructure in a digital university within the conceptual framework of innovative infrastructure for modern organizations, developed a generalized scheme of IT services in a digital university, and elaborated a mathematical apparatus of modified GERT networks to control the processes of heterogeneous services in a digital university. The practical value of the research results is related to the development of new approaches to information management and processes of a modern organization based on the principles of consistency, complexity, and compliance with an appropriate balance between the distribution and integration of data flows. These developments can be replicated with certain modifications to a wide range of organizational and economic systems that are in the stage of digital transformation.
Modeling of the business process of workers' remuneration as an integral part of a balanced scorecard
Authors: Matveeva Helen , Simagina Svetlana , Yuskaeva Daria , Evstafieva Violetta
Published: January 2024

The article is devoted to issues, related to the development of a system of remuneration for workers of a manufacturing enterprise. The enterprise is considered from the point of view of modeling business processes in accordance with the concept of a balanced scorecard (BSC). The importance of modeling the business process of workers remuneration in the context of digital transformation of the enterprise is shown. The efficiency of the entire production process largely depends on the business process of remuneration, which has a significant impact on the efficiency of the enterprise as a whole. The use of computer equipment and information technologies allows not only to form reasonable shift tasks on a daily basis and objectively take into account their implementation, but also to build a fundamentally new remuneration system. In the developed management systems in the conditions of digital transformation, it becomes possible to quickly, differentially and reliably assess the labor results of each employee and the workshop or site as a whole, ensuring economic interest in strictly performing planned shift tasks. The implementation of this method leads to increased motivation and productive, high-quality work, to economical use of material, energy and other resources.
Application of mathematical methods to solving problems of digitization of population movement
Authors: Ketova Karolina , Vavilova Daiana
Published: January 2024

This article is devoted to the development of algorithms and mathematical methods for digitalization of population movement. An algorithm for digitalization of demographic flows is proposed. It becomes possible at any time to obtain a complete description of both a specific person and a general characteristic of the state of the economic system in a given context (for example, age, gender, place of residence, type of settlement, level of education, level of health, level of culture). Within the framework of the problem, four tasks are identified, which the research is aimed at solving. The first task is constructing a scheme of a person's digital trace. The second task is aggregating digital traces and structuring demographic flows and related flows of human capital using Big Data technology. The next task is studying the characteristics, properties and qualities of the said flows using Data-analysis technology. The final task is analyzing and forecasting demographic and human capital flows using Data Science technology. When implementing Data Science technology, the use of mathematical methods of statistical data processing, methods of correlation and regression analysis, mathematical models, forecasting methods, artificial intelligence algorithms, including neural network models, is proposed to solve the task.
Using CloudCompare software editing tools for processing a three-dimensional point cloud of an urban development site
Authors: Gura Dmitry , Karamysheva Ekaterina , Pshidatok Saida
Published: January 2024

This article describes the functions that can be performed by CloudCompare, an open-source triangular mesh and 3D point cloud processing software developed through a collaboration between Telecom ParisTech and EDF R&D. CloudCompare software is used to study and analyze archaeological sites and create their 3D models. Helps engineers monitor the condition of bridges, roads, buildings, etc., identify problems and find solutions to eliminate them. The program provides a set of basic tools for editing and rendering. Some basic editing tools for working in the CloudCompare software are studied and demonstrated, such as cloning, cutting an element from the main object of study, scaling. It is concluded that the CloudCompare software is easy to use and effectively performs the functions contained in it.
CFD simulation of unstable fluid flows in the rotor of a high-speed precipitation centrifuge
Authors: Mordanov Sergey , Khomyakov Anatoly , Gushshamova Victoria , Vlasova Elizaveta , Beloded Mikhail , Shkurin Pavel
Published: January 2024

The results of a numerical study of unstable fluid flows in the rotor of a high-speed vertical precipitation centrifuge are presented. It is shown that during the operation of a high-speed precipitation centrifuge, a qualitative change in the hydrodynamic regime is possible from conditionally laminar to conditionally turbulent, characterized by large-scale axial and radial pulsations of the liquid phase, accompanied by a significant decrease in sedimentation efficiency. It has been established that the flow pulsations are not random in nature, but the amplitude of these pulsations first increases with increasing rotation rate of the centrifuge rotor, and after passing a certain “critical” rotation rate it begins to decrease. Thus, the “critical” rotor rotation rate can be considered as a resonant rate, at which the frequency of turbulent flow pulsations (natural oscillation frequency) coincides with the rotor rotation frequency (forced oscillation frequency). The dependences of the pitch, frequency, and amplitude of liquid flow pulsations on the edge of the centrifuge overflow disk on the rotor rotation rate were obtained. It has been established that in the “subcritical” and “supercritical” operating modes, the amplitude and step of liquid pulsations on the overflow disk of the centrifuge are increasing and decreasing respectively.
Using cooperative coevolution in large-scale black-box constraint satisfaction problems
Authors: Vakhnin Aleksei , Novikov Zakhar
Published: January 2024

Solving constrained large-scale global optimization problems poses a challenging task. In these problems with constraints, when the number of variables is measured in the thousands, when the constraints are presented in the form of a black box, and neither the size nor the configuration of the feasible region is known, it is very difficult to find at least one feasible solution. In general, such a problem of finding a feasible region is known as a constraint satisfaction problem. In this paper, we have extended a well-known benchmark set based on constrained optimization problems up to 1000 variables. We have evaluated the CC-SHADE performance, to tackle constraints in large-scale search space. CC-SHADE merges the power of cooperative coevolution and self-adaptive differential evolution. Our extensive experimental evaluations on a range of benchmark problems demonstrate the strong dependence of the performance of CC-SHADE on the number of individuals and the subcomponent number. The numerical results emphasize the importance of using a cooperative coevolution framework for evolutionary-based approaches compared to conventional methods. All numerical experiments are proven by the Wilcoxon test.
Neural network algorithm for predicting human speed based on computer vision and machine learning
Authors: Obukhov Artem , Teselkin Daniil , Surkova Ekaterina , Komissarov Artem , Shilcin Maxim
Published: January 2024

The problem of increasing the accuracy of predicting human actions is an urgent task for various human-machine systems. The study examines the solution to the problem of predicting human speed using neural network algorithms, computer vision technologies, and machine learning. The formalization and software implementation of a neural network speed prediction algorithm are presented. To solve the problems of determining the current speed and predicting the upcoming positions of the human body depending on the dynamics of its movement, a comparison of various machine learning models was carried out. The RandomForestRegressor algorithm showed the best position prediction accuracy. The best determination of the current speed was demonstrated by dense multilayer neural networks. The experiment revealed that when predicting a person's position at an interval of 0.6 seconds, his speed is determined with an accuracy of more than 90%. The results obtained can be used to implement neural network algorithms for controlling human-machine systems.
Streaming geocoding of incidents based on information from social networks
Authors: Bekeneva Yana , Lopushanskiy Alexandr
Published: January 2024

Users daily publish and discuss information about various kinds of situations occurring in their places of residence (district, city). Sometimes it is necessary to determine the extent to which a situation is affecting the quality of life of citizens, and sometimes published information can be used to identify problems. The work proposes a method for processing text information from messages on social networks and applying geotags, including in real time. The proposed tool can be useful for visualizing certain problems and can be used to make decisions about how to fix those problems.
The automated recognition part markings algorithms
Authors: Kozlov Anton , Ugarova Lyudmila , Loginov Nikolay , Gulyaev Vadim
Published: January 2024

The development is aimed at the problem parts marking recognizing solving in mechanical engineering. Marking makes it possible to ensure the correct parts use and assemblies during assembly, to facilitate the assembly processes automation in production conditions. The algorithms and procedures presented in the article are based on a mathematical apparatus for improving the marking image quality and its recognition. The paper presents a functioning algorithm for the evaluation subsystem and improving the marking image quality based on the processing procedure “sliding window”. A marking recognition algorithm has been developed, the task of which is to recognize the symbols and designations that form the marking. The marking selection procedure result example on the object is given. The proposed algorithms allow for the product markings recognition in production conditions with sufficient reliability.
Enhancing unmanned aerial vehicle capabilities: integrating YOLO algorithms for diverse industrial applications
Authors: Guliutin Nikolai , Antamoshkin Oleslav
Published: January 2024

The integration of UAVs with advanced deep learning algorithms, particularly the You Only Look Once models, has opened new horizons in various industries. This paper explores the transformative impact of YOLO-based systems across diverse sectors, including agriculture, forest fire detection, ecology, marine science, target detection, and UAV navigation. We delve into the specific applications of different YOLO models, ranging from YOLOv3 to the lightweight YOLOv8, highlighting their unique contributions to enhancing UAV functionalities. In agriculture, UAVs equipped with YOLO algorithms have revolutionized disease detection, crop monitoring, and weed management, contributing to sustainable farming practices. The application in forest fire management showcases the capability of these systems in real-time fire localization and analysis. In ecological and marine sciences, the use of YOLO models has significantly improved wildlife monitoring, environmental surveillance, and resource management. Target detection studies reveal the efficacy of YOLO models in processing complex UAV imagery for accurate and efficient object recognition. Moreover, advancements in UAV navigation, through YOLO-based visual landing recognition and operation in challenging environments, underscore the versatility and efficiency of these integrated systems. This comprehensive analysis demonstrates the profound impact of YOLO-based UAV technologies in various fields, underscoring their potential for future innovations and applications.
Application of an effective neural network architecture based on deep learning algorithms for the development of a noninvasive neurocomputer interface
Authors: Karandeev Denis , Karandeeva Irina , Bychkova Irina , Bazhenov Ruslan
Published: January 2024

Abstract. The article highlights the relevance of the development of modern noninvasive neurocomputer interfaces and identifies a problem in their development, which is the low accuracy of decoding human brain activity using modern noninvasive bidirectional neurocomputer interfaces, which makes it difficult to develop fully functioning noninvasive neuroprostheses. This problem is associated with a small number of domestic research in this area, as well as with an insufficient number of necessary tools for the development of this kind of neuroprostheses. The paper presents the principle of operation of this kind of interfaces, as well as varieties of neural interfaces. The scope of application of neurointerfaces and possible prospects for the development of this field are considered. The need to develop an artificial neural network using fuzzy logic aimed at improving the efficiency of isolating and filtering subtle signal patterns and structures of the human brain from the general signal background is justified.
Modeling reflection in artificial intelligence systems: state of art and prospects
Authors: Listopad Sergey , Matsoula Vladimir , Luchko Alexander
Published: January 2024

Abstract. The paper is devoted to analyzing the current state of research and assessing the prospects for modeling reflexive processes using artificial intelligence systems, in particular, multi-agent systems for relevant simulation of collective problem solving. Reflexive modeling of each other by agents will ensure the development of a coherent model of the control object, the purpose of collective work and norms of interaction, as well as the developing of effective interaction between agents. This will allow the system, by self-organizing, to adapt to the characteristics of arising problems, in particular, to take into account their complex structure, the network nature of conditions and goals, opacity, subjectivity and dynamism.
Multi-objective parametric synthesis of loss functions in neural networks with evolutionary algorithms
Authors: Morozov Eduard , Stanovov Vladimir
Published: January 2024

The loss function is a fundamental aspect of neural network training and by choosing a suitable one, better results can be achieved. In classification problems, the cross-entropy loss function is almost exclusively used. In this paper the loss function represented by Taylor's series which are optimized with multi-objective evolutionary algorithm. As results show the new loss function can be better than cross-entropy, however application of multi-objective algorithm does not bring an improvement in comparison with single-objective algorithm.
Mueller matrix imaging polarimeter with polarization camera self-calibration applied to structured light components
Authors: Nabadda Esther , Sánchez-López María del Mar , Vargas Asticio , Lizana Angel , Campos Juan , Moreno Ignacio
Published: January 2024

This work presents a complete Mueller matrix imaging polarimeter that uses three liquid-crystal retarders and a pixelated polarization camera. The polarimeter is characterized and optimized with a standard correction procedure here adapted to be performed fully in-situ, without any additional element, based on considering the polarization camera as the reference. The accuracy limit caused by the extinction ratio in the camera micro-polarizers is analyzed. Finally, the imaging polarimeter is tested experimentally by analyzing well-known samples for structured light applications such as patterned retarders, a patterned polarizer, and a liquid-crystal depolarizer. The work is presented in a tutorial style useful to reproduce the procedure by non-experts in polarimetry.
Propelling plasma thrusters forward for spacecraft
Authors: Patrick Chris
Published: January 2024

Permanent magnets improve performance of magnet nozzle radiofrequency plasma thrusters while saving power.
Who uses yoga and why? Who teaches yoga? Insights from a national survey in New Zealand
Authors: Maddela Sridhar , Buetow Stephen , Teh Ruth , Moir Fiona
Published: January 2024

Introduction Globally, yoga has gained popularity as a health-promoting and disease-prevention discipline. The common health conditions prompting yoga use include musculoskeletal disorders, mental health conditions, asthma, fibromyalgia, arthritis, diabetes, and cancers. Although the therapeutic benefits of using yoga are well documented, little is known about the characteristics of yoga instructors (YIs) and yoga users (YUs) in New Zealand (NZ). Aim This paper seeks to profile the characteristics of NZ YIs and YUs and explore reasons for yoga use. Methods Online surveys for YIs and YUs were conducted to collect the sociodemographic characteristics of 84 YIs and 267 YUs. Descriptive statistics were used to determine trends. Results The surveys were conducted between September 2020 and February 2021. The YIs were predominantly female (87.1%) with mean ± s.d. years of practice of 9.8 ± 0.8 (95% CI: 8.2, 11.4). YUs were most commonly female (86%), of NZ European descent (63%), aged 45–64 years (56%), not married (52.5%), and with a university or higher education qualification (61.5%). They use yoga to alleviate chronic health conditions like back pain (18%), menopausal symptoms (14.5%), anxiety (13.5%) and depression (11.5%). Discussion Most YIs in NZ are females facilitating moderate-sized yoga classes. YUs in NZ are disproportionately NZ European, female, middle-aged and tertiary educated. They use yoga to help manage long-term conditions, including mental ill-health and musculoskeletal disorders. The study findings could inform health professionals regarding the utilisation of yoga in NZ. Further research is required to gain insights into yoga use.
Nutrient-derived signals regulate eosinophil adaptation to the small intestine
Authors: I. Kutyavin Vassily , Korn Lisa L. , Medzhitov Ruslan
Published: January 2024

Eosinophils are well recognized as effector cells of type 2 immunity, yet they also accumulate in many tissues under homeostatic conditions. However, the processes that govern homeostatic eosinophil accumulation and tissue-specific adaptation, and their functional significance, remain poorly defined. Here, we investigated how eosinophils adapt to the small intestine (SI) microenvironment and the local signals that regulate this process. We observed that eosinophils gradually migrate along the crypt–villus axis, giving rise to a villus-resident subpopulation with a distinct transcriptional signature. Retinoic acid signaling was specifically required for maintenance of this subpopulation, while IL-5 was largely dispensable outside of its canonical role in eosinophil production. Surprisingly, we found that a high-protein diet suppressed the accumulation of villus-resident eosinophils. Purified amino acids were sufficient for this effect, which was a consequence of accelerated eosinophil turnover within the tissue microenvironment and was not due to altered development in the bone marrow. Our study provides insight into the process of eosinophil adaptation to the SI, highlighting its reliance on nutrient-derived signals.
Comparison report of the ITS-90 realization at the freezing point of silver between NIM and CMS
Authors: Sun Jianping , Tsai Shu-Fei , Li Ting
Published: January 2024

Main text

The APMP key comparison APMP.T-K4.1 was initiated on the request of the Center for Measurement Standards, Taiwan (CMS) to link their standards to the Consultative Committee for Thermometry (CCT) Key Comparison (KC) and facilitate the CMS CMC submission. National Institute of Metrology, China (NIM) provided the linkage to the CCT-K4 at the temperature of the freezing point of silver. In the APMP.T-K4.1, one high temperature standard platinum resistance thermometer (HTSPRT) was chosen as the transfer instrument and was calibrated at the freezing point of silver. The comparison was carried out in a participant-pilot-participant sequence where NIM served as the pilot. The linkage was based on the temperature of CMS reference Ag fixed point relative to the key comparison reference value (KCRV) of CCT-K4 at the Ag fixed point via the difference in temperature between the NIM reference Ag fixed point and NIM reference Ag fixed point (links to the KCRV of the CCT-K4). The temperature difference between the standards of CMS and the KCRV of the CCT-K4 was within the evaluated comparison uncertainties of the ATPM.T-K4.1. This report provides detailed information on the comparison results, linkage mechanism, and the Degree of Equivalence of the CMS relative to the institutes having participated in the CCT-K4.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Update of the BIPM comparison BIPM.RI(II)-K1.Zn-65 of activity measurements of the radionuclide 65Zn to include the 2015 result of the LNMRI-IRD (Brazil) and the 2018 result of the LNE-LNHB (France)
Authors: Michotte Carine , Courte Sammy , Coulon Romain , Nonis Manuel , Ratel Guy , Judge Steven , Fréchou Carole , Bobin Christophe , Silva C J da , Silva R L da , Delgado J U , Rangel J A
Published: January 2024

Main text

Since 1977, 19 laboratories have submitted 22 samples of 65Zn to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)- K1.Zn-65. The LNMRI-IRD (Brazil) and the LNE-LNHB (France) are the latest participants in the comparison and the key comparison reference value (KCRV) has been updated. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical representation is also given.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Degradation of electrical performance and radiation damage mechanism of cascode GaN HEMT with 80 MeV proton
Authors: Lu Yuxin , Cao Rongxing , Li Hongxia , Yang Xuelin , Zeng Xianghua , Xue Yuxiong
Published: January 2024

In this paper, proton irradiations on Cascode GaN HEMT power device with an energy of 80 MeV and fluences of 2 × 1011 p/cm2 and 6 × 1011 p/cm2 have been carried out, where the threshold voltages drifted negatively by 20.55% and 28.17%, respectively. After two months of room temperature annealing, the threshold voltages recovered 0.22 V and 0.27 V, respectively. The ionizing deposition energy (IEL) was simulated by using Monte Carlo software and TCAD, it the results showed that the value of IEL in Si MOSFET is 5 ∼ 6 orders higher than that in GaN HEMT, while the value of the non-ionizing energy loss (NIEL) is one order higher than that in GaN HEMT. It means that the proton irradiation on the Cascode depleted GaN HEMT is more prone to produce displacement damage. As a large number of electrons and holes pairs were existed on the incident path of Si MOSFET under the proton irradiation, the produced electron will be captured by the gate oxide traps at the SiO2/Si interface, and the holes be captured by the defects generated in displacement damage, resulting in the accumulation of oxide trapped charges. Then, the electrical performance of Si MOSFET degrades seriously, thereby affecting the performance of the entire device. The studies will be helpful for the radiation hardening of Cascode GaN HEMT.
Experimental demonstration of the criterion for the prepare-and-measure nonclassicality
Authors: Luo Maolin , Zhang Xiaoqian , Zhou Xiaoqi
Published: January 2024

The prepare-and-measure theory is a new type of quantum paradox that reveals the incompatibility between classical theory and quantum mechanics in terms of the dimensionality of physical systems. Just as the Horodecki criterion can determine whether given quantum states are capable of exhibiting Bell nonclassicality, a similar criterion is needed for the prepare-and-measure theory to determine whether given quantum states can exhibit the prepare-and-measure nonclassicality. Recently, Poderini et al [Phys. Rev. Research 2, 043 106 (2020)] presented such a criterion for the prepare-and-measure nonclassicality. In this work, we experimentally validate this criterion—52 different sets of quantum states are prepared and tested one by one using this criterion to determine whether they can exhibit the prepare-and-measure nonclassicality, and the experimental results are in good agreement with the theoretical expectations. The criterion experimentally verified here has the potential to be widely used in future research on the prepare-and-measure nonclassicality.
The general set of Noetherian energy-momentum tensors in linearized gravity: mathematical framework
Authors: Taylor Lydia Beth , Baker Mark Robert
Published: January 2024

Energy-momentum tensors are foundational objects which are uniquely defined in standard physical field theories such as electrodynamics and Yang-mills theory. In general relativity, and in particular linearized gravity where symmetries required for an energy-momentum tensor derived from Noether’s first theorem are well defined, there exists a long standing non-uniqueness problem; numerous distinct energy-momentum expressions exist in the literature, and there is not consensus which, if any, is the unique expressions for the theory. Recently, the viability of the superpotential ‘improvement’ method was shown to be insufficient for addressing the non-uniqueness problem of energy-momentum tensors in linearized gravity. In the present article, the mathematical framework for the general set of Noetherian energy-momentum tensors in linearized gravity is derived using Noether’s first theorem, which consists of all possible energy-momentum tensors from the Noether current which yield the linearized Einstein field equations in the corresponding Euler-Lagrange equation of the Noether identity without introducing any ‘improvement’ terms. This result has several advantages in addition to not requiring ‘improvements’, such as the ability to impact the Lagrangian proportional piece of the energy-momentum tensor. Numerous common published gravitational energy-momentum expressions are then compared to these general results to assess which can be classified as Noetherian, and which cannot. Standard physical criteria such as symmetry and tracelessness are then used to prove that it is possible to directly obtain an energy-momentum tensor which is simultaneously symmetric and traceless from the Noether current; such an expression is derived from the general results. Consequences of these results and their relation to the aforementioned non-uniqueness problem are discussed.
No accelerating scaling cosmologies at string tree level?
Authors: Riet Thomas Van
Published: January 2024

We investigate the scalar potential in the parametric regime of string moduli space where string loops and higher derivative corrections to 10d supergravity can be ignored and where the fields are rolling down exponential slopes leading to powerlaw FLRW cosmologies, a.k.a. scaling solutions. We argue that these scaling solutions, if describing an accelerating expansion, are likely to be perturbatively unstable, for reasons identical to the perturbative instabilities in tree-level dS vacua.
A novel dual-channel thermo-optic locking method for the whispering gallery mode microresonator
Authors: Fan 范 Wenjie 文杰 , Liu 刘 Wenyao 文耀 , Pan 潘 Ziwen 梓文 , Wang 王 Rong 蓉 , Liu 刘 Lai 来 , Xing 邢 Enbo 恩博 , Zhou 周 Yanru 彦汝 , Tang 唐 Jun 军 , Liu 刘 Jun 俊
Published: January 2024

Mode locking can be effectively achieved by using the thermo-optic effects in the whispering gallery mode (WGM) optical microcavity, without the help of external equipment. Therefore, it has the advantages of small size, low integration costs, and self-locking, which shows great potential for application. However, the conventional single-channel microcavity thermal-locking method that relies solely on internal thermal balance will inevitably be disturbed by the external environment. This limitation affects the locking time and stability. Therefore, in this paper, we propose a new method for closed-loop thermal locking of a dual-channel microcavity. The thermal locking of the signal laser and the thermal regulation of the control laser are carried out respectively by synchronously drawing a dual-path tapered fiber. The theoretical model of the thermal dynamics of the dual-channel microcavity system is established, and the influence of the control-laser power on the thermal locking of the signal laser is confirmed. The deviation between the locking voltage of the signal laser and the set point value is used as a closed-loop feedback parameter to achieve long-term and highly stable mode locking of the signal laser. The results show that in the 2.63 h thermal-locking test, the locking stability is an order of magnitude higher than that of the single tapered fiber. This solution addresses the issue of thermal locking being disrupted by the external environment, and offers new possibilities for important applications such as spectroscopy and micro-optical sensor devices.
Microfluidics assisted optics manufacturing technique
Authors: Long Yan , Dai Bo , Zhang Dawei
Published: January 2024

The conventional micro/nano-manufacturing techniques can hardly process interior microstructures. The entire fabrication process is complex and requires large-footprint and high-cost equipment. The presented microfluidics assisted optics manufacturing technique is feasible to create the curved surface inside microstructure using various modified materials. The fabrication process is simple. Only small, low-cost devices are needed. In this paper, microfluidics assisted optics manufacturing technique is introduced in detail and compared with the current manufacturing techniques. A diversity of interesting micro-optics, including microlens array and compound eye, are demonstrated. These optical components are all fabricated by the microfluidics assisted manufacturing technique and possess their own outstanding features.
Hot processing map and high temperature deformation behaviour of TB17 Ti alloy
Authors: Fan Hao , Chen Xing , Cui Xia , Ouyang Delai , Jiang Jianfei , You Long , Ding Weijie , Xie Youmei , Wang Saihang
Published: January 2024

The thermal compression experiments of TB17 titanium alloy under different thermal deformation process parameters were carried out using a thermal simulation compressor. The high-temperature plastic flow behaviour of the alloy was studied. It was found that with the decrease of the deforming temperature and the increase of the strain rate, the flow stress increased, and the discontinuous yield phenomenon occurred in hot deformation. The larger the strain rate, the more obvious the discontinuous yield phenomenon. The thermal activation energy Q decreased with the increase of strain, and the average value of activation energy Q is 209.54 KJ / mol. The constitutive equation of high-temperature plastic flow of TB17 titanium alloy was established. The predicted values of this equation are in good agreement with the experimental values. The average error is 3.987 %, and the correlation coefficient is 0.9972, which has high accuracy. Based on the Prasad criterion, the hot processing map of TB17 titanium alloy was constructed. It was found that the flow instability zone was mainly concentrated in the high strain rate region. The flow instability zone was determined to be 795 °C ~ 895 °C, 0.046s-1 ~ 1s-1, and the stable deformation zone was mainly located in the region with high temperature and low strain rate. The optimum processing parameter range is 860 °C ~ 895 °C, 0.001 s-1 ~ 0.025 s-1.
A Novel Application of High Thermal Conductivity Material on Superconducting RF Cavities: The Inner-wall Thermal Conducting Film (ITCF)
Authors: Luo Didi , Li Jianpeng , Yang Ziqin
Published: January 2024

Superconducting Radiofrequency (SRF) technology has developed rapidly for the requirements of high-energy accelerators in fundamental physics research and nuclear industry applications. Thus, the SRF community endeavored to improve the performance from every aspect for niobium and thin-film cavities and made significant breakthroughs in the past decades. However, the positive feedback effect from the RF loss seriously limits the cavity’s maximum acceleration gradient and causes the high field’s unstable operation. Mitigating this effect requires increasing the cavity thermal conductivity to reduce the temperature at the heating point. Conventional technology conducts the RF-loss heat from the surface to the liquid helium outside the cavity while the inner cavity remains vacuum. This paper introduces a new strategy which coats an inner-wall thermal-conducting film (ITCF) in the cavity for the first time globally. The COMSOL simulation results show that ITCF absorbs heat from the RF surface and transmits the heat to the distance on the inner wall, generating a different heat transfer route, thereby reducing the heating-point temperature more efficiently.
Thermodynamic databases of Ti-Al-Fe-V quaternary alloy systems and its application
Authors: Zhang Yeqin , Wang Wenwen , Zhang Hongyu , Liu Libin , Huang Lijun
Published: January 2024

Pandat software based on Calculations of phase diagram (CALPHAD) was used in this study. Six binary systems and four ternary systems in the Ti-Al-Fe-V system were evaluated, compared, and optimized. A thermodynamic database of Ti-Al-Fe-V titanium alloys was established by selecting the most recent, accurate, and self-consistent thermodynamic parameters. The database was used to simulate the organization of equilibrium solidification and non-equilibrium solidification alloys of Ti-10V-2Fe-3Al, Ti-10V-3Al-1Fe and Ti-10V-3Al. The precipitated phase fractions of Ti-10V-2Fe-3Al at different temperatures were calculated using the database. The effect of different Fe contents and aging temperatures on the phase composition of the Ti-10V-2Fe-3Al alloy is given in conjunction with the calculated results. There is good agreement with the experimental results for the heat treatment regimens given by the calculations. The above results show that thermodynamic calculations based on phase diagrams can guide the formulation of process parameters for alloy casting and heat treatment. The established thermodynamic database for Ti-Al-Fe-V titanium alloys is accurate and reliable.
Corrosion Evolution mechanism of N80 tubing steel under supercritical CO2 and H2S environment
Authors: Ding T C , Zhao Y L , Yang D H , Sun C , Sun J B , Lin X Q
Published: January 2024

The corrosion evolution mechanism of N80 tubing steel in 8 MPa supercritical CO2 and 0.1 MPa H2S environment was investigated. The results show that although the corrosion rate of N80 steel decreases with the prolonged corrosion time, it still maintains a high level of about 1.06 mm/y after a long period of 360 h. As the corrosion progresses, the corrosion products change from FeS to a mixture of FeS and FeCO3. The corrosion form of N80 steel changes from uniform corrosion to localized corrosion. The origin credited for localized corrosion is the detachment of large particles of FeS in the early corrosion stage. A double-layer film consisting of an outer layer of FeS and an inner layer of FeCO3 forms in the area of corrosion pits after a prolonged period of corrosion, which provides protection for the substrate, thereby causing the decrease of localized corrosion rate of N80 steel.