bluuebunny/crossref_metadata_2025 huggingface dataset:
Predictors of Survival in Patients with Metastatic Brain Tumors: Experience from a Low-to-Middle-Income Country
Authors: Anis Saad Bin , Hani Ummey , Yousaf Irfan
Published: March 2023

Objective The interplay of static factors and their effect on metastatic brain tumor survival, especially in low-to-middle-income countries (LMICs), has been rarely studied. To audit our experience, and explore novel survival predictors, we performed a retrospective analysis of brain metastases (BM) patients at Shaukat Khanum Memorial Cancer Hospital (SKMCH), Pakistan.

Materials and Methods A retrospective review was conducted of consecutive patients who presented with BM between September 2014 and September 2019 at SKMCH. Patients with incomplete records were excluded.

Statistical Analysis SPSS (v.25 IBM, Armonk, New York, United States) was used to collect and analyze data via Cox-Regression and Kaplan–Meier curves.

Results One-hundred patients (mean age 45.89 years) with confirmed BM were studied. Breast cancer was the commonest primary tumor. Median overall survival (OS) was 6.7 months, while the median progression-free survival (PFS) was 6 months. Age (p = 0.001), gender (p = 0.002), Eastern Cooperative Oncology Group (p < 0.05), anatomical site (p = 0.002), herniation (p < 0.05), midline shift (p = 0.002), treatment strategies (p < 0.05), and postoperative complications (p < 0.05) significantly impacted OS, with significantly poor prognosis seen with extremes of age, male gender (hazard ratio [HR]: 2.0; 95% confidence interval [CI]: 1.3–3.1; p = 0.003), leptomeningeal lesions (HR: 5.7; 95% CI: 1.1–29.7; p = 0.037), and patients presenting with uncal herniation (HR: 3.5; 95% CI: 1.9–6.3; p < 0.05). Frontal lobe lesions had a significantly better OS (HR: 0.5; 95% CI: 0.2–1.0; p = 0.049) and PFS (HR: 0.08; 95% CI: 0.02–0.42; p = 0.003).

Conclusion BM has grim prognoses, with comparable survival indices between developed countries and LMICs. Early identification of both primary malignancy and metastatic lesions, followed by judicious management, is likely to significantly improve survival.
Seroprevalence of Toxoplasmosis in Puerperal Women Treated at a Tertiary Referral Hospital
Authors: Medeiros Juliana Fernandes , Rabelo e Silva Ana Cláudia , Rocha Natália Domene Franco da , Georg Alexia Viegas , Melli Patricia Pereira dos Santos , Quintana Silvana Maria , Duarte Geraldo
Published: March 2023

Objective To evaluate the seroprevalence of toxoplasmosis among puerperal women cared for at a tertiary university hospital and the level of understanding of these puerperal women about toxoplasmosis, vertical transmission, and its prophylaxis.

Methods For this cross-sectional study, we evaluated 225 patients using presential interviews, prenatal documentation, and electronic medical records. Data were stored using Research Electronic Data Capture (REDCap) software. Prevalence rates were estimated by the presence of reactive IgG antibodies against Toxoplasma gondii. Data analysis was performed using the chi-square test and calculation of the odds ratio (OR). Seroreactivity to T. gondii and exposure variables (age, educational level, and parity) were analyzed using a confidence interval (95%CI) and a significance level of 5% (p < 0.05).

Results The seropositivity rate for T. gondii was 40%. There was no association between seroprevalence and age. Primiparity was a protective factor against seropositivity and low education was a risk factor.

Conclusion Knowledge of T. gondii infection and its transmission forms was significantly limited, presenting a risk for acute maternal toxoplasmosis and vertical transmission of this protozoan. Increasing the education level regarding the risk of toxoplasmosis during pregnancy could reduce the rates of infection and vertical transmission of this parasite.
Dual-Task Paradigm Measures of Listening Effort: To Include or Not to Include Secondary Task Responses with Incorrect Primary Task Responses
Authors: Huang Haiping , Oosthuizen Ilze , Picou Erin M.
Published: March 2023

Response time–based dual-task paradigms are commonly adopted to measure behavioral listening effort. Most extant studies used an all-response approach that included secondary task responses under both correct and incorrect primary task responses during analysis. However, evidence supporting this strategy is limited. Therefore, the current study investigated the potential differences between including all responses versus only including correct responses. Data from two previous studies were reanalyzed. Experiment 1 included 16 listeners and used a dual-task paradigm to examine the effect of introducing background noise on listening effort. Experiment 2 included 19 participants and used a different dual-task paradigm to examine the effect of reverberation and loudspeaker-to-listener distance on listening effort. ANOVA results obtained using both analysis approaches were compared. The all-response and correct-only approaches revealed similar results. However, larger effect sizes and an additional main effect were found with the all-response approach. The current study supports the use of an all-response approach due to its greater sensitivity to changes in behavioral listening effort. However, a correct-only approach could be utilized to suit specific study purposes.
Combining Multiple Psychophysiological Measures of Listening Effort: Challenges and Recommendations
Authors: Richter Michael , Buhiyan Tanveer , Bramsløw Lars , Innes-Brown Hamish , Fiedler Lorenz , Hadley Lauren V. , Naylor Graham , Saunders Gabrielle H. , Wendt Dorothea , Whitmer William M. , Zekveld Adriana A. , Kramer Sophia E.
Published: March 2023

About one-third of all recently published studies on listening effort have used at least one physiological measure, providing evidence of the popularity of such measures in listening effort research. However, the specific measures employed, as well as the rationales used to justify their inclusion, vary greatly between studies, leading to a literature that is fragmented and difficult to integrate. A unified approach that assesses multiple psychophysiological measures justified by a single rationale would be preferable because it would advance our understanding of listening effort. However, such an approach comes with a number of challenges, including the need to develop a clear definition of listening effort that links to specific physiological measures, customized equipment that enables the simultaneous assessment of multiple measures, awareness of problems caused by the different timescales on which the measures operate, and statistical approaches that minimize the risk of type-I error inflation. This article discusses in detail the various obstacles for combining multiple physiological measures in listening effort research and provides recommendations on how to overcome them.
Post-identifiability in changing sociotechnological genomic data environments
Authors: Akyüz Kaya , Goisauf Melanie , Chassang Gauthier , Kozera Łukasz , Mežinska Signe , Tzortzatou-Nanopoulou Olga , Mayrhofer Michaela Th.
Published: March 2023

Data practices in biomedical research often rely on standards that build on normative assumptions regarding privacy and involve ‘ethics work.’ In an increasingly datafied research environment, identifiability gains a new temporal and spatial dimension, especially in regard to genomic data. In this paper, we analyze how genomic identifiability is considered as a specific data issue in a recent controversial case: publication of the genome sequence of the HeLa cell line. Considering developments in the sociotechnological and data environment, such as big data, biomedical, recreational, and research uses of genomics, our analysis highlights what it means to be (re-)identifiable in the postgenomic era. By showing how the risk of genomic identifiability is not a specificity of the HeLa controversy, but rather a systematic data issue, we argue that a new conceptualization is needed. With the notion of post-identifiability as a sociotechnological situation, we show how past assumptions and ideas about future possibilities come together in the case of genomic identifiability. We conclude by discussing how kinship, temporality, and openness are subject to renewed negotiations along with the changing understandings and expectations of identifiability and status of genomic data.
Thermodynamic analysis of a typical compressed air energy storage system coupled with a fully automatic ejector under slip pressure conditions
Authors: Zhang Yufei , Yao Erren , Li Ruixiong , Sun Hao , He Xin , Wang Huanran , Xu Huijuan
Published: March 2023

To solve the problem of energy loss caused by the use of conventional ejector with fixed geometry parameters when releasing energy under sliding pressure conditions in compressed air energy storage (CAES) system, a fully automatic ejector capable of adjusting key geometric parameters to maintain the maximum ejection coefficient by an automatic control device according to the running parameters is proposed in this paper. By establishing a thermodynamic model of a typical CAES system coupled with a fully automatic ejector, the effect of the fully automatic ejector on the system performance is studied under sliding pressure conditions. The results show that the fully automatic ejector has the most sensitive ejection coefficient with the variation of high-pressure gas pressure. The cycle efficiency and exergy efficiency of the proposed system were 56.91% and 52.64%, respectively. Compared with the coupled conventional ejector, the cycle efficiency, exergy efficiency, and output power of the system were increased by 0.93%, 0.81%, and 4.59%, respectively. The exergy loss of the combustion chamber is the largest among the components within the system, accounting for 65.2% of the total exergy loss, followed by the heat exchanger, which accounts for 13.8% of the exergy loss, while the fully automatic ejector has the smallest exergy loss, accounting for only 0.8% of the total exergy loss. When the extraction point is at the first stage of the turbine, the system cycle efficiency and external energy efficiency vary parabolically with the extraction pressure, but the system performance will change abruptly when the pressure at the extraction point approaches 1.5 MPa. The system performance index is more sensitive to the change of turbine inlet temperature than other variables. Reducing the heat exchanger heat transfer temperature difference and increasing the fully automatic ejector outlet pressure are the effective ways to improve system performance.
High-throughput piezoelectric droplet dispenser driven by ultra-low voltage
Authors: Li Dege , Wang Jide , Yang Guodong , Wu Xinlei , Li Zihao , Hu Guofang , Wang Xiaolong , Liu Yonghong , Zhang Yanzhen
Published: March 2023

Efficient and facile generation of tiny droplets is critical to many cutting-edge applications, such as flexible electronic skin, customized circuits, and micro-electro-mechanical systems. However, conventional piezoelectric inkjet printing techniques show more prominent problems of high driving voltage and relatively low printing frequency. Here, a novel principle for high-throughput droplet dispensing was proposed based on the resonance of the liquid column within the glass capillary. The mechanisms of this high-throughput piezoelectric droplet dispensing technique were studied both experimentally and theoretically. It is demonstrated experimentally that the resonance frequencies of different orders of the liquid column in the capillary fit perfectly with the theoretical value. It is further demonstrated that when the working frequency is close to the resonant frequency of piezoelectric ceramic, droplets can be ejected out by a driving voltage as low as 1 V. This ultra-low driving voltage and power consumption make this dispenser compatible with various digital transistor–transistor logic or complementary metal–oxide–semiconductor drive circuits without any power amplifier.
Productivity and semantic transparency
Authors: Tian Shen , Baayen R. Harald
Published: March 2023

We used word embeddings to study the relation between productivity and semantic transparency. We compiled a dataset with around 2700 two-syllable compounds that shared position-specific constituents (henceforth pivots) and some 1100 suffixed words. For each pivot and suffix, we calculated measures of productivity as well as measures of semantic transparency. For compounds, productivity (P) was negatively correlated with the number of types (V) and with the semantic similarity between non-pivot constituents and their compounds. Conversely, the greater semantic similarity of the pivot with either the compound or the non-pivot constituent predicted higher degrees of productivity. Visualization with t-SNE revealed clustering of suffixed words’ embeddings, but no by-pivot clustering for compounds, except for a minority of pivots whose regions in semantic space did not contain intruding unrelated compounds. A subset of these pivots was found to realize a fixed shift in semantic space from the base word to the corresponding compound, a property that also emerged for several suffixes. For these pivots, no correlation between P and V was present. Thus, Mandarin compounds appear to realize, at one extreme, motivated but unsystematic concept formation (where other pivots could just as well have been used), and at the other extreme, systematic suffix-like semantics.
A new formulation of general-relativistic hydrodynamic equations using primitive variables
Authors: Servignat Gaël , Novak Jérôme , Cordero-Carrión Isabel
Published: March 2023

We present the derivation of hydrodynamical equations for a perfect fluid in General Relativity, within the

3
+
1

decomposition of spacetime framework, using only primitive variables. Primitive variables are opposed to conserved variables, as defined in the widely used Valencia formulation of the same hydrodynamical equations. The equations are derived in a covariant way, so that they can be used to describe any configuration of the perfect fluid. Once derived, the equations are tested numerically. We implement them in an evolution code for spherically symmetric self-gravitating compact objects. The code uses pseudospectral methods for both the metric and the hydrodynamics. First, convergence tests are performed, then the frequencies of radial modes of polytropes are recovered with and without the Cowling approximation, and finally the performance of our code in the black hole collapse and migration tests are described. The results of the tests and the comparison with a reference core-collapse and neutron star oscillations code suggests that not only our code can handle very strong gravitational fields, but also that this new formulation helps gaining a significant amount of computational time in hydrodynamical simulations of smooth flows in General Relativity.
Improving the intrinsic conductance of selective area grown in-plane InAs nanowires with a GaSb shell
Authors: Khelifi W , Coinon C , Berthe M , Troadec D , Patriarche G , Wallart X , Grandidier B , Desplanque L
Published: March 2023

The nanoscale intrinsic electrical properties of in-plane InAs nanowires grown by selective area epitaxy are investigated using a process-free method involving a multi-probe scanning tunneling microscope. The resistance of oxide-free InAs nanowires grown on an InP(111)B substrate and the resistance of InAs/GaSb core–shell nanowires grown on an InP(001) substrate are measured using a collinear four-point probe arrangement in ultrahigh vacuum. They are compared with the resistance of two-dimensional electron gas reference samples measured using the same method and with the Van der Pauw geometry for validation. A significant improvement of the conductance is achieved when the InAs nanowires are fully embedded in GaSb, exhibiting an intrinsic sheet conductance close to the one of the quantum well counterpart.
A compact, friction self-matching, non-inertial piezo motor with scanning capability
Authors: Zhao Kesen , Hou Yubin , Zheng Shaofeng , Wang Jihao , Lu Yalin , Meng Wenjie , Lu Qingyou
Published: March 2023

Maintaining friction matching is the core issue for non-inertial piezo motors (PMs); this challenge severely limits their application in complex conditions such as variable temperature environments. To address this issue, a compact, optimal friction self-matching PM with non-inertial driving is reported in this paper. The motor is implemented with a narrow 5.5 mm-outer diameter piezoelectric scanner tube (PST) whose outer electrode is equally divided into two independently controllable PSTs. The PST, divided into two parts, clamps a sapphire rod between dual sapphire ball structures at both ends and an elastically supported sapphire ball at the centre. The device features a balanced normal force distribution scheme that allows friction forces acting on the sapphire rod at both ends and on the intermediate section to be approximately equal along the axial direction of the PST, achieving automatic optimal matching of friction, then it can operate like an inchworm motor. The feasibility of this scheme is verified by testing with a low threshold voltage down to 35 V at room temperature and 160 V at liquid nitrogen temperature. The motor dimensions are 5.5 mm × 5.5 mm ×35 mm (length × width × height). At room temperature, step size ranges from 0.1 μm to 1 μm. It has a maximum stroke about 5 mm and a maximum load of 40 g. This PM’s extreme compactness, low machine tolerance requirements, and smooth sequence make it ideally suited for building superior quality, atomically resolved scanning probe microscopy devices compatible with narrow spaces and extreme conditions.
Constraints on Yukawa gravity parameters from observations of bright stars
Authors: Jovanović P. , Borka Jovanović V. , Borka D. , Zakharov A.F.
Published: March 2023

In this paper we investigate a Yukawa gravity modification of the Newtonian gravitational
potential in a weak field approximation. For that purpose we derived the corresponding equations
of motion and used them to perform two-body simulations of the stellar orbits. In 2020 the GRAVITY
Collaboration detected the orbital precession of the S2 star around the supermassive black hole
(SMBH) at the Galactic Center (GC) and showed that it is close to the general relativity (GR)
prediction. Using this observational fact, we evaluated parameters of the Yukawa gravity (the
range of Yukawa interaction Λ and universal constant δ) with the Schwarzschild
precession of the S-stars assuming that the observed values as indicated by the GRAVITY
Collaboration will have a small deviation from GR prediction [1]. GR provides the most
natural way to fit observational data for S-star orbits, however, their precessions can be fitted
by Yukawa gravity. Our main goal was to study the possible influence of the strength of Yukawa
interaction, i.e. the universal constant δ, on the precessions of S-star orbits. We analyze
S-star orbits assuming different strength of Yukawa interaction δ and find that this
parameter has strong influence on range of Yukawa interaction Λ. For that purpose we use
parameterized post-Newtonian (PPN) equations of motion in order to calculate the simulated orbits
of S-stars in GR and Yukawa gravity. Using MCMC simulations we obtain the best-fit values and
uncertainties of Yukawa gravity parameters for S-stars. Also, we introduce a new criterion which
can be used for classification of gravitational systems in this type of gravity, according to
their scales. We demonstrated that performed analysis of the observed S-stars orbits around the GC
in the frame of the Yukawa gravity represent a tool for constraining the Yukawa gravity parameters
and probing the predictions of gravity theories.
The Dirac equation on metrics of Eguchi–Hanson type
Authors: Cai Zhuohua , Zhang Xiao
Published: March 2023

We investigate parallel spinors on the Eguchi–Hanson metrics and find the space of complex parallel spinors is complex two-dimensional. For the metrics of Eguchi–Hanson type with the zero scalar curvature, we separate variables for the harmonic spinors and obtain the solutions explicitly.
Si–Ge based vertical tunnel field-effect transistor of junction-less structure with improved sensitivity using dielectric modulation for biosensing applications
Authors: Agarwal Lucky , Mishra Varun , Dwivedi Ravi Prakash , Goyal Vishal , Tripathi Shweta
Published: March 2023

A dielectric modulation strategy for gate oxide material that enhances the sensing performance of biosensors in junction-less vertical tunnel field effect transistors (TFETs) is reported. The junction-less technique, in which metals with specific work functions are deposited on the source region to modulate the channel conductivity, is used to provide the necessary doping for the proper functioning of the device. TCAD simulation studies of the proposed structure and junction structure have been compared, and showed an enhanced rectification of 104 times. The proposed structure is designed to have a nanocavity of length 10 nm on the left- and right-hand sides of the fixed gate dielectric, which improves the biosensor capture area, and hence the sensitivity. By considering neutral and charged biomolecules with different dielectric constants, TCAD simulation studies were compared for their sensitivities. The off-state current I
OFF can be used as a suitable sensing parameter because it has been observed that the proposed sensor exhibits a significant variation in drain current. Additionally, it has been investigated how positively and negatively charged biomolecules affect the drain current and threshold voltage. To explore the device performance when the nanogaps are fully filled, half filled and unevenly filled, extensive TCAD simulations have been run. The proposed TFET structure is further benchmarked to other structures to show its better sensing capabilities.
Single-electron transport in H2O@C60 single-molecule transistors
Authors: Liu Bowen , Chen Jun , Ouyang Yiping , Zhang Minhao , Tan Yuan-Zhi , Song Fengqi
Published: March 2023

Single-molecule transistors (SMTs) based on fullerenes and their derivatives have been recognized as a long-sought platform for studying the single-electron transport properties. H2O@C60 is a combination of fullerene and H2O, a typical light molecule. Here we use the ‘molecular surgery’ technique to synthesize the H2O@C60 molecule and then construct the H2O@C60 SMTs, together with the C60 SMTs. Evidences for single-electron transport have been obtained in our measurements, including explicit Coulomb blockade and Coulomb oscillations. We then calculate the detailed parameters of the H2O@C60 and C60 SMTs using a capacitance model derived from the Coulomb diamond feature, which gives a capacitance ratio of 1:5.05:8.52 for the H2O@C60 SMT and 1:29.5:74.8 for the C60 SMT. Moreover, the gate efficiency factor α turns out to be 0.0686 in the H2O@C60 SMT, about ten times larger than that in the C60 SMT. We propose that the enhanced gate efficiency in H2O@C60 SMT may be induced by the closer attachment of molecular orbital electron clouds to the gate substrate due to polarization effects of H2O.
Saturated absorption spectrum of cesium micrometric-thin cell with suppressed crossover spectral lines
Authors: Han Junlong , Wang Bowen , Zheng Junhe , Chen Shuyuan , Xiao Wei , Wu Teng , Guo Hong , Peng Xiang
Published: March 2023

Micrometric-thin cells (MCs) with alkali vapor atoms have been valuable for research and applications of hyperfine Zeeman splitting and atomic magnetometers under strong magnetic fields. We theoretically and experimentally study the saturated absorption spectra using a 100-μm cesium MC, where the pump and probe beams are linearly polarized with mutually perpendicular polarizations, and the magnetic field is along the pump beam. Because of the distinctive thin chamber of the MC, crossover spectral lines in saturated absorption spectra are largely suppressed leading to clear splittings of hyperfine Zeeman transitions in experiments, and the effect of spatial magnetic field gradient is expected to be reduced. A calculation method is proposed to achieve good agreements between theoretical calculations and experimental results. This method successfully explains the suppression of crossover lines in MCs, as well as the effects of magnetic field direction, propagation and polarization directions of the pump/probe beam on saturated absorption spectrum. The saturated absorption spectrum with suppressed crossover lines is used for laser frequency stabilization, which may provide the potential value of MCs for high spatial resolution strong-field magnetometry with high sensitivity.
Orderly hysteresis in field-driven robot swarm active matter
Authors: Liu Yanping , Wang Gao , Wang Peilong , Yuan Daming , Hou Shuaixu , Jin Yangkai , Wang Jing , Liu Liyu
Published: March 2023

Boundary effect and time-reversal symmetry are hot topics in active matter. We present a biology-inspired robot-environment-interaction active matter system with the field-drive motion and the rules of resource search, resource consumption, and resource recovery. In an environmental compression–expansion cycle, the swarm emerges a series of boundary-dependent phase transitions, and the whole evolution process is time-reversal symmetry-breaking; we call this phenomenon “orderly hysteresis”. We present the influence of the environmental recovery rate on the dynamic collective behavior of the swarm.
Stochastic fluctuations in the rotation of the bacterial flagellar motor
Authors: Yue Guanhua , Zhang Rongjing , Yuan Junhua
Published: March 2023

The bacterial flagellar motor is a nanometer-sized rotary motor that generates the torque to drive the rotation of the flagellar filament. The output torque is an important property of the motor. The motor rotation was usually monitored by attaching a μm-sized bead to a shortened flagellar filament, and the torque was extracted by calculating the torque due to the viscous drag of the medium on the bead rotation. We sought for an independent extraction of the torque from thermal fluctuation in the motor rotation using the fluctuation theorem (FT). However, we identified an overwhelming fluctuation beyond the thermal noise that precluded the use of FT. We further characterized the timescale and the amplitude of this fluctuation, finding that it was probably due to the stepping of the motor. The amplitude of torque fluctuation we characterized here provided new information on the torque-generating interaction potential curve.
Perspectives of spin-valley locking devices
Authors: Tao 陶 Lingling 玲玲
Published: March 2023

Valleytronics is an emerging field of research which utilizes the valley degree of freedom to encode information. However, it is technically nontrivial to produce a stable valley polarization and to achieve efficient control and manipulation of valleys. Spin–valley locking refers to the coupling between spin and valley degrees of freedom in the materials with large spin–orbit coupling (SOC) and enables the manipulation of valleys indirectly through controlling spins. Here, we review the recent advances in spin–valley locking physics and outline possible device implications. In particular, we focus on the spin–valley locking induced by SOC and external electric field in certain two-dimensional materials with inversion symmetry and demonstrate the intriguing switchable valley–spin polarization, which can be utilized to design the promising electronic devices, namely, valley-spin valves and logic gates.
Critical behavior in the epitaxial growth of two-dimensional tellurium films on SrTiO3 (001) substrates
Authors: Zhang Haimin , Song Dezhi , Huang Fuyang , Zhang Jun , Jiang Ye-Ping
Published: March 2023

Materials’ properties may differ in the thin-film form, especially for epitaxial ultra-thin films, where the substrates play an important role in their deviation from the bulk quality. Here by molecular beam epitaxy (MBE) and scanning tunneling microscopy/spectroscopy, we investigate the growth kinetics of ultra-thin tellurium (Te) films on SrTiO3 (STO) (001). The MBE growth of Te films usually exhibits Volmer–Weber (VW) island growth mode and no a-few-monolayer film with full coverage has been reported. The absence of wetting-layer formation in the VW growth mode of Te on STO (001) is resulted from its low diffusion barriers as well as its relatively higher surface energy compared with those of the substrate and the interface. Here we circumvent these limiting factors and achieve the growth of ultra-thin β-Te films with near-complete coverages by driving the growth kinetics to the extreme condition. There is a critical thickness (3 monolayer) above which the two-dimensional Te films can form on the STO (001) substrate. In addition, the scanning tunneling spectra on the ultra-thin Te film grown on STO exhibits an enormously large forbidden gap compared with that grown on the graphene substrate. Our work establishes the necessary conditions for the growth of ultra-thin materials with similar kinetics and thermodynamics.
Studies of Heavy Pear-shaped Nuclei
Authors: Butler P A
Published: March 2023

For certain combinations of protons and neutrons it is expected that the shape of atomic nuclei can undergo octupole deformation, which would give rise to reflection asymmetry or a “pear shape”. Here it is described how recent experiments carried out at CERN using REX-ISOLDE and HIE-ISOLDE and the Miniball gamma-ray spectrometer have provided evidence that several radium and radon isotopes have either stable pear shapes or are octupole vibrational in nature. It will be shown that the data on transition moments present some challenges for theory. The relevance of these measurements for atomic EDM searches, and the future prospects for this field, will also be discussed.
Rare weak decays and neutrino mass
Authors: Kotila Jenni
Published: March 2023

The question whether neutrinos are Majorana fermions (i.e., their own anti-particles) remains among the most fundamental open questions of subatomic physics. If neutrinos are Majorana particles it would revolutionize our understanding of physics. Although neutrinoless double beta decay, 0νββ, was proposed more than 80 years ago to establish the nature of neutrinos, it remains the most sensitive probe into the non-conservation of lepton number. 0νββ-decay is a postulated extremely slow and yet unobserved radioactive process in which two neutrons (or protons) inside a nucleus transform into two protons (or neutrons) emitting two electrons (or positrons), respectively, but no neutrinos. Its observation would be a breakthrough in the description of elementary particles and would provide fundamental information on the neutrino masses, their nature, and origin. In this paper double beta decay, its connection to neutrino mass, and mechanisms beyond the standard mass mechanism are discussed from a theoretical point of view. The current situation is then addressed by combining theoretical results with recent experimental limits.
Lepton- and baryon-number violation in nuclear effective field theory
Authors: van Kolck U
Published: March 2023

Lepton and baryon numbers are accidental symmetries in the effective field theory (EFT) of the Standard Model. Their violation would lead to spectacular nuclear decays which can be described with nuclear EFTs. I discuss ways in which two such decays — the neutrinoless double-beta decay of heavy nuclei and the disappearance of the deuteron — provide complementary information to processes that take place outside the nuclear environment — neutrino masses, nucleon decay, and neutron-antineutron oscillations.
Zr isotopes as a case study for intertwined quantum phase transitions
Authors: Gavrielov N.
Published: March 2023

The scenario of intertwined quantum phase transitions (IQPTs) is identified in the Zr isotopes with neutron numbers 52–70, and shown to involve both a crossing of normal and intruder configurations and a shape-evolution within each configuration. Using the framework of the interacting boson model with configuration mixing, this situation is demonstrated by a quantum analysis of the spectra, E2 transition rates, order parameters, symmetry and configuration content of the wave functions and a classical analysis of energy surfaces.
Nuclear structure aspects of the heaviest N∼Z nuclei south of 100Sn
Authors: Górska M. , Albers H. M. , Arici T. , Banerjee A. , Benzoni G. , Blazhev A. , Cederwall B. , Das B. , Davinson T. , Gerl J. , Grawe H. , Hall O. , Hubbard N. , Jazrawi S. , Jolie J. , Mikołajczuk M. , Mistry A. K. , Mengoni D. , Podolyák Zs. , Polettini M. , Regan P. H. , Rüdigier M. , Yaneva A. , Vesic J. , Zhang G.
Published: March 2023

Ever-lasting interest in the structure of 100Sn and neighbouring nuclei is still well justified by the fact that it is the heaviest doubly-magic nucleus with N=Z. State-of-the-art experimental techniques involving stable and radioactive beam facilities have enabled access to these exotic nuclei. In particular, the analysis of experimental data obtained in two DESPEC experiments at GSI Darmstadt extends the information on the shell structure and its evolution towards N = Z = 50, and allows the study of seniority conservation and proton-neutron interaction in the g9/2 orbit. Several theoretical approaches for shell-model investigations are discussed and their predictive power assessed. The calculated systematics of the reduced transition probabilities for high- to medium-spin states in N∼Z isotopes with active g9/2 orbit is presented for the first time.
Relativistic Brueckner-Hartree-Fock Theory: an ab initio Approach for Nuclear Matter and for Finite Nuclei
Authors: Ring Peter , Wang Sibo , Tong Hui , Zhao Qiang , Wang Chencan , Meng Jie
Published: March 2023

Recent years have seen considerable progress with ab-initio calculations of the nuclear structure by non-relativistic many-body methods. Dirac-Brueckner-Hartree-Fock Theory provides a relativistic ab-intio approach, which is able to reproduce saturation properties of symmetric nuclear matter without three-body forces. However, so far, the corresponding equations have been solved only for positive energy states. Negative energy states have been included for forty years in various approximations, leading to differences in the isospin dependence. This problem has been solved only recently by a complete solution of the self-consistent relativistic Brueckner-Hartree-Fock equations in asymmetric nuclear matter. Due to its numerical complexity, however, it is very difficult to extend the Relativistic Brueckner-Hartree-Fock theory to the study of finite nuclear systems. Recent efforts will be discussed to overcome this problem.
Architecture design for civil aircraft hydraulic system
Authors: Chen Cai , Wang Xu , Zhou Changming
Published: March 2023

The hydraulic system is a highly complex system for civil aircraft. System Engineering is a method to solve complex and comprehensive problems. To reduce the development risk, this paper establishes a hydraulic system architecture design model based on system engineering using system ideas and analysis methods. With this model, several aspects of hydraulic system architecture design are discussed, including input, requirements analysis, functional analysis, system synthesis, and system balance.
Experimental study of flow in a cavity with the variable shape at a low Reynolds number
Authors: Liu Yuan , Liu Peiqing , Guo Hao
Published: March 2023

The flow structure of a cavity with a length-to-depth ratio of 2:1. In this experiment, the particle image velocimetry (PIV) technique was used to experimentally research the front and rear wall inclined cavity configurations with different inclinations. The experiments were carried out in a recirculating water tank. The configurations with front and rear wall inclination angles of 26°, 45°, and 56° were compared at the same incoming flow velocity. A total of seven different configurations are given for the comparison of several variables. In addition, the flow velocity, Reynolds stress and turbulence intensity values were measured and analyzed for all configurations. Correlation analysis is used to reveal the shear layer evolution process, and the outcomes indicate that the wall inclination changes the shape and size of the shear layer. The coherent structures of shear layers with different cavity shapes are identified in combination with appropriate proper orthogonal decomposition (POD). Different shapes of the cavity configuration may vary the size of the shear layer. The calculation of turbulence intensity also shows that the cavity configuration with the largest inclination angle has the largest cavity turbulence intensity at the centreline cross-section.
Research and Verification on the Solution of Pressure Fluctuation of the Fan Air Inlet of Civil Aircraft Pneumatic System
Authors: Peng Danqi
Published: March 2023

The cold side bleeds air of the precooler in the pneumatic system of civil aircraft is usually drawn out from the external bypass of the engine fan and enters the precooler for heat exchange through the fan air inlet, bellows, and fan air valve. When the fan air valve is closed, a closed dead cavity is formed in the fan air inlet. When the airflow passes through the mouth at high speed, the pressure of the fan air inlet into the mouth will oscillate at high frequency, resulting in pressure fluctuation, which will lead to the damage of the bellows and the loss of bleed air function. CFD is proposed in this paper. The method of dynamic simulation combined with limited test parameters successfully located the root causes of the fan air inlet pressure fluctuations, solved the fan air inlet pressure fluctuation phenomenon, and creatively put forward the fan air inlet with hat, fan air inlet with ventilation branch 2 broad categories, and 8 kinds of potential solution design train of thought. CFD simulation method is used to analyze and compare each potential solution in detail. Finally, the solution was selected according to the test results and applied to the aircraft.
Analysis of Load-Enhanced Factor(LEF) of MIL-P-25690B Acrylic Glass
Authors: Ma Yinglong
Published: March 2023

MIL-P-25690B acrylic glass is one of the primary materials currently used in transparent structural components of civil aircraft. In order to shorten the time of fatigue tests and reduce the cost, the load-enhanced factor (LEF) method is used for fatigue tests. The fatigue test load multiplies the LEF, which is amplified in the fatigue test. LEF, sample sizes, and fatigue test duration are correlated according to the CMH-17 composite materials handbook. According to MIL-P-25690B acrylic glass, the test scheme of LEF is determined; test results, test data analysis, and processing method are given. The relationship between LEF and the corresponding test duration under certain conditions is obtained, which provides a theoretical basis and analysis support for fatigue tests of transparent parts of civil aircraft.
Application of CFD Numerical Simulation Methods in the Field of UAV Research
Authors: Hu Xupei , Liu Junhao , Yang Fanfu , Yuan Mu
Published: March 2023

Unmanned aerial vehicle (UAV) has become one of the hot topics in today’s research. A drone’s short life has always been one of the main drawbacks, and fluid mechanics is related to the development of computer technology. CFD was used to simulate the aerodynamic parameters of UAVs and has become a more economical choice, which can greatly save the cost of materials. Solid-liquid coupling calculation generally chooses the SST k - Ω model to calculate and will also include an energy equation in the calculation. Then, according to the precision needs to choose a different order of upwind format. Choose either steady state or transient simulation according to different needs. CFD is widely used in research on the overall stability and reliability of UAVs and the experiment on the aerodynamic characteristics of UAV components.
Study on the Influence of Low-Frequency Flow Oscillation on the Atomization Characteristics of Gas-Centered Coaxial Centrifugal Nozzle
Authors: Kang Jinxin , Tong Yiheng , Jiang Chuanjin , Feng Songjiang , Shao Mingxue
Published: March 2023

The dynamic atomization characteristics of gas center coaxial centrifugal nozzle under the condition of pressure oscillation in the supply system were studied by applying external excitation through the flow pulsator. Obtaining spray image by high-speed photography while using hydro-mechanical pulsator to get generate of supply system. The results show that the spray width changes periodically with low-frequency pressure oscillation. For self-pulsation sprays, it is challenging to maintain a “Christmas tree” shape with low-frequency oscillation. Pressure oscillation can effectively suppress spray self-pulsation. However, the pressure oscillation amplitude may be much larger than that of the self-pulsation itself. Therefore, the premise of applying this method is that the applied external excitation cannot stimulate or amplify the combustion instability. The gas post-pressure drop determines the amplitude and frequency of the self-pulsation, while the excitation frequency will slightly affect the amplitude and frequency of the self-pulsation.
Sound Insulation Performance of the Stiffened Laminated Plate with Different Reinforcement Forms
Authors: Bu Y L , Chen L , Wang H F
Published: March 2023

A semi-analytical methodology on the sound transmission of stiffened laminated plate under different reinforcement forms is developed to explore its sound insulation performance under the action of a plane sound wave load, in accordance with the classical laminated plate theory and in consideration of stiffener flexion and torsional motions. The formula of acoustic transmission loss is obtained by utilizing spatial harmonic expansion and the virtual work principle. Subsequently, the predicted values of proposed methodology are validated by the existing models. Eventually, some characteristic parameters are considered to investigate their effects on sound insulation behavior.
Dual Mesh Technique for Hydroacoustic Prediction of Cavitating Flows around a Three-Dimensional Bullet
Authors: Yu Lianjie , Zhao Weiwen , Wan Decheng
Published: March 2023

Nowadays, hydroacoustics is of great importance. A major source of underwater noise is cavitation noise. One of the difficulties in cavitation noise prediction is its complex formation mechanism. In this paper, a cavitating bullet is taken as the research object, and detailed numerical simulation research of the local cavitation for this three-dimensional model is carried out. Ffowcs Williams and Hawkings equation (FW-H) is adopted. The quadrupole term is obtained by the direct volume integration method. Furthermore, dual mesh technique is adopted to achieve fast calculation. The results show that the dual mesh technology reduces the computational complexity of the nonlinear sound pressure significantly. With the appropriate acoustic grid size, the dual mesh method can ensure the same accuracy as the CFD grid. This provides a reliable way for the calculation of nonlinear sound pressure in the cavitation phenomenon.
Performance Study of External Scaffolding under Wind-Induced Action
Authors: Cao Qian , Huang Yiyang , Chen Bo , Wu Pengjin , Zhang Sheng , Ma Liang , Wei Lilong , Huang Lepeng
Published: March 2023

Scaffolding is an essential temporary measure in engineering construction, and its safety management is critical in the construction process. In this paper, the overall scaffolding model is simulated and analyzed by SAP2000 finite element software. The difference in force between the scaffolding under static wind load and time-range wind load is obtained so that the wind vibration coefficient of the scaffolding is suggested. The results show that the most influential factor in the stability of the scaffold is the way in which the wall elements are arranged. At the same time, the most favorable arrangement is a two-step, two-span arrangement of the wall elements, a 50° angle of scissor bracing, and a wind protection factor of 0.8 for the safety net. Also, the wind vibration factor βz should be taken as 2.5 instead of 1 in the scaffolding code for close-meshed scaffolding at a height of 50 m.
Integrated Valve Product Fluid Simulation and Test Verification
Authors: Li Leilei , Liu Baorong , Gong Shengbo , Zhao Jian , Tao Qiang , Zhou Xu , Xu Yingli , Guo Menglei
Published: March 2023

The integrated valve product’s main function is to electrolytic oxygen generation subsystem to produce hydrogen and oxygen to realize automatic discharge, to maintain the space station astronauts in orbit around in comfort and safety, high reliability, easy maintenance, and the device should be easy replacement of human-computer ergonomics requirements to ensure long-term on-orbit operation station. Based on the above requirements, an integrated valve product based on environmental control and a health protection system is designed. The integrated product includes hydrogen normal and backup emission branches, oxygen normal and backup emission branches. Through fluid simulation and experimental verification, it is verified that the flow rate and other key indicators of the integrated valve product meet the requirements, which has certain reference and guiding significance for the design of similar integrated products in the future.
A Control Algorithm of Active Wave Compensation System Based on the Stewart Platform
Authors: Wu Huiyuan , Yang Wenlin , Ong Muk Chen , Fan Tianhui , Yin Guang , Zeng Weixiang , Situa Weilun , Wang Yunting
Published: March 2023

Aim at the actual engineering requirements of wind power operation and maintenance under complex sea conditions, a control method of the active wave compensation system for maintenance ships based on the Stewart platform is presented. The kinematics of the platform is analyzed, and the coordinate transformation, pose, and inverse solutions are analyzed and calculated. The multi-body dynamics simulation model is established by using MATLAB. For the problem of the load nonlinearity and strong coupling of the nonlinear Stewart platform, an active wave compensation active disturbance rejection control (ADRC) is built to attain the high-precision control of the six-degree-of-freedom (6-DOF) Stewart platform. The numerical simulation shows that the proposed control scheme has good tracking accuracy and strong anti-interference ability.
Schwinger-Dyson Equations-of-Motion Method for Quantum Spin-1/2
Authors: Dai Chuanru , Ding Wenxin
Published: March 2023

The essential difficulty of a large portion of the strongly interacting systems can be traced down to the “noncanonicality” of the underlying operators which are used to formulate the theory, like t-J model, Hubbard-type models in the large-U limit, quantum spin, etc. We proposed a new Schwinger-Dyson equations-of-motion method to compute the dynamical correlation functions of quantum spins at zero temperature. This method can also compute all the static observables from the dynamical correlation functions. We propose that this method can formulate dynamical perturbation calculations for quantum spin-1/2 models.
Experimental research on damage tolerance and air tightness of typical composite panels
Authors: Zou Peng , Wang Qingsong , Chen Hao , Yang Junchao , Li YinSong
Published: March 2023

The extensive use of composites in aircraft leads to the problem of damage tolerance after low-speed impact. It is necessary to consider not only the change of mechanical properties but also the change of work properties such as air tightness. In this paper, the damage morphology and air tightness of a typical composite stiffened panel subjected to low-speed impact were experimentally studied. The damage initiation and propagation and the change of air tightness after impact, static compression and compression fatigue were analyzed respectively. It is found from the test that after 120% ultimate load condition and 100,000 times constant amplitude fatigue load condition, the impact damage does not expand, and the air tightness is good and no obvious leakage is observed, indicating that the structural design meets the requirements of damage tolerance and air tightness.