bluuebunny/crossref_metadata_2025 huggingface dataset:
Diagnostic Value of T1 Mapping in Detecting Iron Overload in Indian Patients with Thalassemia Major: A Comparison with T2* Mapping
Authors: Singh Surya Pratap , Jagia Priya , Ojha Vineeta , Seth Tulika , Naik Nitish , Ganga Kartik P. , Kumar Sanjeev
Published: September 2023

Purpose T2* is the gold standard for iron quantification in liver as well as myocardium. In this study, we evaluated the diagnostic accuracy of myocardial T1 mapping for the assessment of myocardial iron overload (MIO) as compared to the T2* mapping in patients with thalassemia major (TM).

Methods Consecutive TM patients attending the thalassemia clinic were prospectively enrolled. Magnetic resonance imaging was performed on a 1.5 T scanner (Siemens Healthineers, Germany) using a gradient echo T2* as well as a T1 mapping (MOLLI) sequence done at a mid-ventricular short-axis single 8 mm slice of the left ventricle. Values were analyzed by manually drawing a region of interest in the mid-septum. T2*less than 20ms was used as the cutoff for significant MIO.

Results One-hundred three patients (58 males, mean age: 17 ± 7.8 years, mean ferritin: 2009.5 µg/L) underwent cardiovascular magnetic resonance. Median T2* of myocardium was 33.45ms. Nineteen patients (18.4%) had T2*less than 20ms. T1 value was low (<850ms) in all the patients with T2* less than 20 ms. Receiver operating characteristic curve analysis revealed the best cutoff of native T1 mapping value as 850 ms which had high specificity (95.2%), sensitivity (94.2%) and negative predictive value (98.8%) for T2* less than 20ms. There was excellent agreement between T1 and T2* for diagnosis of MIO (Kappa—0.848, p <0.001). We did not find any patient who had normal T1 mapping values but had MIO on T2*.

Conclusion T1 and T2* correlate well and normal T1 values may rule out presence of MIO. T1 mapping can act as additional imaging marker for MIO and may be helpful in centers with nonavailability or limited experience of T2*.
Dorsal Wrist Carpal Boss Impingement—Dynamic Ultrasound to the Rescue!
Authors: Agarwal Aakanksha , Murray Timothy E. , Cresswell Mark , Chandra Abhishek
Published: September 2023

The “carpal boss” is a variant present in 19% of the population according to cadaveric studies but becomes symptomatic in only 1% of cases. With the rising popularity of “yoga,” which includes prolonged hyperextension at the wrist joint with weight bearing, an increasing number of individuals with silent carpal boss present with dorsal wrist pain due to impingement over the dorsal soft tissues by this innocuous bony protuberance. This warrants the attention of radiologists and clinicians while dealing with wrist pain. It can be challenging to identify this bossing on routine radiographs, necessitating special views. We describe the use of dynamic ultrasound in diagnosing “symptomatic” carpal boss, the effects of which become even more evident on imaging during hyperextension—the triggering movement.
Management of Post Radiotherapy Radionecrotic Ulcer in Carcinoma Breast Patients Using Tram Flap
Authors: Biswas Gautam
Published: September 2023

Radiation as a modality of management in malignancy, especially for carcinoma of breast is well established. However, the deleterious effect of radiation on normal tissue, is still witnessed. Four patients of advanced breast malignancy, who underwent radical mastectomy followed by adjuvant radiotherapy presented with radiation ulcers of the chest, between 1993-1994. Soft tissue break down over the irradiated site occurred as late as two to three years following irradiation. All patients were tumour negative.

Excision of involved irradiated tissue was followed by reconstruction using the pedicled Transverse Rectus Abdominis Myocutaneous Flap (TRAM). This fulfilled the twin goals of well vascularized flap coverage and restoration of form in a single stage.
Air Fluidized Support System in the Management of Major Burns
Authors: Malhotra S , Bharat R
Published: September 2023

Thirty-two patients with major burns over the back of trunk and limbs were treated on the Air fluidized support system (Clinitron) and the results were compared with a control group of patients treated on conventional beds. It was found that in the group treated on Clinitron bed, mortality was lower, graft take was better, pressure sores did not develop and the patients were more comfortable. The results have been compared to similar studies. Though the initial investment and maintenance cost is very high, the device offers immense benefits, especially ease in nursing care.
Validation of triglyceride and glucose index as a rapid diagnostic test to diagnose insulin resistance in pregnant and lactating sows
Authors: Ortiz Ruy , López Manuel , Pérez Rosa E. , Ordaz Gerardo
Published: September 2023

Context In sows, the development of insulin resistance (IR) during late gestation and lactation favours a productive gap associated with low feed intake during lactation, which is reflected in the herd profitability. Therefore, the development of rapid-use tests to diagnose IR on farms will be very useful. Aims We aimed to validate the triglyceride and glucose (T-G) index as a rapid diagnostic test to diagnose IR in sows during late gestation and lactation. Methods The homeostatic model to evaluate IR (HOMA-IR) was used as a reference. Sixty sows (farrowing 1–5) were selected for blood sampling during late gestation and lactation. In the total number of samples collected (n = 480), the glucose, insulin, and triglyceride concentrations were determined to estimate the HOMA-IR and T-G index. Receiver operating characteristic curves were used to determine cut-off values for diagnosing IR using the T-G index. Key results The highest (P < 0.05) values of HOMA-IR and T-G index were found between Day 110 of gestation and Day 3 of lactation, regardless of the farrowing number evaluated. The area under the curve for the T-G index was 0.83 (95% CI 0.78–0.88). The best overall cut-off point for diagnosing IR by using the T-G index was 4.24 (86% sensitivity and 77% specificity). The association between the T-G index and HOMA-IR was 0.68 (P < 0.0001), regardless of the farrowing number and productive stage (late gestation, early lactation, and late lactation). According to the farrowing number and productive stage, the best cut-off points were 4.21 (sensitivity 86% and specificity 73%), 4.20 (sensitivity 83% and specificity 73%), and 4.20 (sensitivity 88% and specificity 92%) for sow’s first and fourth farrowing, and late gestation respectively. Conclusions The T-G index is a reliable field test for IR diagnosis in sows during late gestation and lactation. Implications The T-G index test evaluated for the diagnosis of IR in sows is an approach that could be significantly exploited at the farm level. This test could become a support tool to maximise the productivity of the sow, since the development of IR could be modulated through zootechnical practices.
Conservation biological control of insect pests
Authors: Emden Helmut F.
Published: September 2023

Conservation biological control increases the control effect of locally occurring natural enemies and has two approaches. Ecological engineering of the agroecosystem involves improving the environment in favour of natural enemies. The second approach is to devise ways of improving the ratio of natural enemies to pests by applying an insecticide in a partially selective manner. The tools of ecological engineering are to provide pollen and nectar sources as an adult food for beneficial insects, to increase floral diversity to increase the numbers of other insects that provide alternative food for beneficials, perhaps to add a single plant species to support an essential alternate host for a predator or parasitoid, or to use plant diversity to raise humidity in the crop. These tools have long been available, but have only been exploited more recently as the public and governments have required greater environmental sustainability and pests have increasingly become tolerant to the available insecticides. Few insecticides offer intrinsic selectivity in favour of natural enemies, but selectivity of broad-spectrum compounds can be obtained by reducing the dose of the insecticide or by restricting its application in time or space. Whatever approach is considered, its practical application is usually quite simple.
Improved tensile strength of welded AlSi10Mg alloys by using laser metal deposition
Authors: Wang Can , He Dingyong , Cui Li , Shi Zhenfu , Guo Xingye , Wu Xu , Zhai Yingying , Bu Fanhui
Published: September 2023

Laser metal deposition process was introduced to join AlSi10Mg alloys fabricated by powder bed fusion-laser beam/metal to improve the tensile strength of laser welded joints. The size and the porosity of the hydrogen pores in the weld seam are significantly reduced by laser metal deposition welding. The ultimate tensile strength of the welded joint by using laser metal deposition reaches 318.8 MPa, and the microhardness of the weld seam ranges from 99.5 to 105.4 HV. Compared with single-pass welding, the ultimate tensile strength and hardness are increased by 60.6% and 27.6%. This is mainly attributed to the reduced porosity, refined α-Al structures and increased connectivity of the Si-rich networks of the weld seam achieved by laser metal deposition welding.
Plurigaussian conditional simulation (PGS) of the Budenovskoe uranium roll-front deposit, central Kazakhstan: 3D model of the host sedimentary sequence
Authors: Abzalov M. , Renard D.
Published: September 2023

The current paper presents case study of the Budenovskoe sandstone-hosted uranium deposit, the host sequence of which has been modelled geostatistically, using Plurigaussian conditional simulation (PGS) and Sequential Gaussian conditional simulation (SGS). The PGS method minimises subjectivism of the geological interpretations, by constraining the lithological models to geostatistical and lithostratigraphic characteristics of the host sequence, and accurately reproduces litho-stratigraphy of the sedimentary sequence, realistically conveying its complexity. This was integrated with the rock permeability generated using SGS. Integrating two models has significantly enhanced definition of the fluid infiltration passages in the host sequence. The model was built using stochastic algorithms of PGS and SGS, and therefore can be used for estimation the project risk. In practice, the errors, initially estimated to the blocks used for the conditional simulation, are grouped to the volumes of a practical interest, including the resource and reserve domains, production blocks and the leach cells.
Ultrathin internal dielectric electrostatic actuator for reduced pull-in voltage and bidirectional actuation
Authors: Verma Satish K , Mitra Bhaskar
Published: September 2023

Direction and analog deflection control, as well as low voltage digital switching are the most desirable attributes in electrostatic actuators for current MEMS applications. In this work we show how internal dielectric transduction can be used to reduce pull-in voltages without reducing the air gap, and to effect bi-directional actuation. The actuator is a metal–dielectric–metal sandwich. For hybrid actuation to achieve reduced pull-in, the device has a thick bottom metal and a thin top metal, while for the upward actuator the device has a thick top metal and a thin bottom metal. An out-of-plane deflection of 108 nm is achieved using 5 V applied voltage for the upward actuator, while the hybrid actuator shows over 50% reduction in pull-in voltage from 1.26 V to 0.62 V.
Friedel oscillation in non-Fermi liquid: lesson from exactly solvable Hatsugai–Kohmoto model
Authors: Zhao Miaomiao , Yang Wei-Wei , Luo Hong-Gang , Zhong Yin
Published: September 2023

When non-magnetic impurity immerses in Fermi sea, a regular modulation of charge density around impurity will appear and such phenomena is called Friedel oscillation (FO). Although both Luttinger liquid and Landau Fermi liquid show such characteristic oscillation, FO in generic non-Fermi liquid (NFL) phase is still largely unknown. Here, we show that FO indeed exists in NFL state of an exactly solvable model, i.e. the Hatsugai–Kohmoto model which has been intensively explored in recent years. Combining T-matrix approximation and linear-response-theory, an interesting picture emerges, if two interaction-induced quasi-particles bands in NFL are partially occupied, FO in this situation is determined by a novel structure in momentum space, i.e. the ‘average Fermi surface’ (average over two quasi-particle Fermi surface), which highlights the inter-band particle-hole excitation. We hope our study here provides a counterintuitive example in which FO with Fermi surface coexists with NFL quasi-particle, and it may be useful to detect hidden ‘average Fermi surface’ structure in other correlated electron systems.
Emulating learning behavior in a flexible device with self-formed Ag dewetted nanostructure as active element
Authors: Yadav Bhupesh , Mondal Indrajit , Bannur Bharath , Kulkarni Giridhar U
Published: September 2023

Neuromorphic devices are a promising alternative to the traditional von Neumann architecture. These devices have the potential to achieve high-speed, efficient, and low-power artificial intelligence. Flexibility is required in these devices so that they can bend and flex without causing damage to the underlying electronics. This feature shows a possible use in applications that require flexible electronics, such as robotics and wearable electronics. Here, we report a flexible self-formed Ag-based neuromorphic device that emulates various brain-inspired synaptic activities, such as short-term plasticity and long-term potentiation (STP and LTP) in both the flat and bent states. Half and full-integer quantum conductance jumps were also observed in the flat and bent states. The device showed excellent switching and endurance behaviors. The classical conditioning could be emulated even in the bent state.
Threshold distribution of equal states for quantitative amplitude fluctuations
Authors: Yao Wenpo , Yao Wenli , Wang Jun
Published: September 2023

Objective. The distribution of equal states (DES) quantifies amplitude fluctuations in biomedical signals. However, under certain conditions, such as a high resolution of data collection or special signal processing techniques, equal states may be very rare, whereupon the DES fails to measure the amplitude fluctuations. Approach. To address this problem, we develop a novel threshold DES (tDES) that measures the distribution of differential states within a threshold. To evaluate the proposed tDES, we first analyze five sets of synthetic signals generated in different frequency bands. We then analyze sleep electroencephalography (EEG) datasets taken from the public PhysioNet. Main results. Synthetic signals and detrend-filtered sleep EEGs have no neighboring equal values; however, tDES can effectively measure the amplitude fluctuations within these data. The tDES of EEG data increases significantly as the sleep stage increases, even with datasets covering very short periods, indicating decreased amplitude fluctuations in sleep EEGs. Generally speaking, the presence of more low-frequency components in a physiological series reflects smaller amplitude fluctuations and larger DES. Significance. The tDES provides a reliable computing method for quantifying amplitude fluctuations, exhibiting the characteristics of conceptual simplicity and computational robustness. Our findings broaden the application of quantitative amplitude fluctuations and contribute to the classification of sleep stages based on EEG data.
Hints of granular superconductivity in natural graphite verified by trapped flux transport measurements
Authors: Champi Ana , Precker Christian E , Esquinazi Pablo D
Published: September 2023

This study describes electrical transport measurements as a function of magnetic field and temperature that provide hints of the existence of superconductivity with a critical temperature of

T
c

∼
350

K in a natural graphite sample. The measurements were done in a restricted temperature 300 K

⩽
T
⩽
450

K and magnetic field

B
⩽
400

mT range. Electrical resistance measurements at remanence (zero field), after the application of a magnetic field, indicate the existence of trapped flux, which remains nearly unchanged within

∼

30

min but it vanishes at a temperature of

∼

330

K. The apparent transition is accompanied by a clear enhancement of the magnetoresistance at

T
<

T
c

. Raman measurements on the bulk sample reveal the existence of the rhombohedral stacking order, which interfaces with the usual Bernal phase were predicted to lead to high temperature superconductivity due to the formation of robust flat bands in the electron dispersion relation.
Charged anisotropic tolman IV solution in matter-geometry coupled theory
Authors: Sharif M , Naseer Tayyab
Published: September 2023

This paper discusses the interior distribution of several anisotropic star models coupled with an electromagnetic field in the context of

f
(

,

,

)

gravity, where


=



β
ξ



β
ξ

. In this regard, a standard model of this modified gravity is taken as


+

ν

3



β
ξ



β
ξ

, where ν
3 symbolizes an arbitrary coupling constant. We assume a charged spherically symmetric metric that represents the interior geometry of compact quark stars and develop the corresponding modified field equations. These equations are then solved with the help of metric potentials of Tolman IV spacetime and a linear bag model equation of state. We consider the experimental data (i.e. radii and masses) of different quark models such as SMC X-4, SAX J 1808.4-3658, Her X-I and 4U 1820-30 to analyze how the charge and modified corrections affect their physical characteristics. The viability and stability of the resulting model is also checked for the considered star candidates with two different values of ν
3. We conclude that only two models, Her X-I and 4U 1820-30 show stable behavior in this modified framework for both values of the coupling constant.
Time-frequency analysis of radon and thoron data using continuous wavelet transform
Authors: Rasheed Awais , Osama Muhammad , Rafique Muhammad , Tareen Aleem Dad Khan , Lone Kashif Javed , Qureshi Shahzad Ahmad , Kearfott Kimberlee Jane , Alam Aftab , Nikolopoulos Dimitrios
Published: September 2023

Continuous exposure to environmental radiation, whether it derives from natural or artificial sources, is thought to pose a substantial risk to public health. In addition to the health effects associated with prolonged exposure to environmental radiations, long-term measurements of these radiations can be used for a variety of beneficial purposes, such as the forecasting of impending earthquakes. Signal processing is an important application used for the purpose of forecasting. Wavelets, being signal-processing tools, are helpful in many applications such as anomaly detection in time series data. However, selection of the best wavelet for a particular application is still a problem that hasn’t found a satisfactory solution. In this study, we used continuous wavelet transform (CWT) on environmental radiations, specifically radon time series (RTS) and thoron time series (TTS) data, for the investigation of time-frequency information (TFI). The distribution of energy in the output wavelet decomposition have been investigated by several wavelet families such COIF4, DB4, SYM4 to detect frequency composition of signal and its relation with anomalies hidden in the observed data. Using discrete wavelet transform (DWT), specifically SYM4, DB4, and COIF4, we transformed the radon and thoron time series into a time-dependent sum of frequency components. Using CWT scalograms, the anomalies in the both of time series datasets (TSD) have been identified, and these anomalies have been associated with the seismic events that occurred during the period of the study. The results show that DB4 and SYM4 wavelets are good at identifying anomalies in original radon and thoron TSD, but SYM4 performs better for DWT-decomposed radon and thoron TSD.
Computational insight into the fundamental physical properties of ternary ABCl3 chloroperovskites compounds using the DFT approach
Authors: Husain Mudasser , Albalawi Hind , Huwayz Maryam Al , Al Saqri Noor alhuda , Khan Rajwali , Rahman Nasir
Published: September 2023

In this research, the ternary non-centrosymmetric chloroperovskites compounds of the form ABCl3 (A = Rb and B = Be, Mg) are investigated extensively to predict the structural, mechanical, and optoelectronic properties with DFT incorporated in WIEN2K code. The crystalline structure of interested chloroperovskites is identified to be cubic, non-centrosymmetric, and stable. The elastic constants Cij, bulk modulus, criteria of Pugh ratio, and the Born criteria confirm the ductility and mechanical stability of ternary RbBeCl3 and RbMgCl3 materials. Electronic properties such as the band structures and density of states are examined with the most widely recognized TB-mBJ potential approximation. RbBeCl3 shows semiconducting behaviour with an indirect wide band gap energy of 3.74 eV from R-Γ symmetries points, while RbMgCl3 is assumed to be an insulator that possesses indirect wide band gap energy of 6.28 eV from R-Γ. It is identified that the ABCl3 (A = Rb and B = Be, Mg) non-centrosymmetric compounds change the behavior from wide band gap semiconductors to perfect insulators when the ‘B’ site in ABCl3 varies from ‘Be’ to ‘Mg’ element. In the electromagnetic range from 0 eV to 40 eV of incident photons energy, several parameters in optical properties that includes the dielectric function, refractive index, absorption coefficient, optical conductivity, extinction coefficient, and energy loss function are investigated for the quest of potential applications of interested non-centrosymmetric cubic systems in modern photovoltaic technologies. These outcomes may add inclusive understanding within ultraviolet ranges for photovoltaic applications.
Improving the electrochemical and physical properties of nickel cobaltite /polyacrylonitrile nanocomposites for supercapacitor applications
Authors: Shoubak Walaa M , Hassan A , Mahrous S , Hassen A
Published: September 2023

Nanocomposite films composed of polyacrylonitrile (PAN) doped with nickel cobaltite (NCO) nanoparticles (NPs) with different weight ratios have been prepared and characterized. Field emission scanning electron microscopy (FE-SEM) confirmed that the NCO NPs were successfully incorporated into the PAN matrix. The x-ray diffraction (XRD) studies showed that the PAN degree of crystallinity was lowered by the incorporation of NCO NPs in the polymer matrix. Other various characterization techniques including energy dispersive x-ray (EDX), Fourier transform infrared (FTIR), and thermal analysis were used. In addition, the effect of NCO NPs on the dielectric permittivity and ac-conductivity exhibits that the ac conductivity of PAN is enhanced from 0.06 ×10− 4 to 3.19 ×10− 4 S m−1 by doping with 10 wt% NCO NPs at room temperature (RT) and 1.0 MHz. Moreover, the optical properties showed that the NCO/PAN nanocomposites revealed lower transmittance and narrowed the optical bandgap (E
g) of the PAN from 3.92 to 3.37 eV. Cyclic voltammetry (CV), and galvanostatic charge–discharge (GCD) tests were performed to investigate the electrochemical behavior of the studied nanocomposites. It was found that PAN loaded with 10 wt% NCO NPS attains an excellent specific capacitance of 1241 F g−1 at a current density of 0.5 A/g. Also, the cycling stability is significantly enhanced, and the capacitance retention rate approaches 93.2% after 5000 cycles, which provides the possibility of using the studied nanocomposite films for supercapacitor applications.
Morphological, optical and electrochemical properties of tin(II) 2,3-naphthalocyanine for organic electronic applications
Authors: Hassanien A M , AlHazaa Abdulaziz N , Atta A A , Altalhi Tariq A , Refat Moamen S , Mersal Gaber A M , Almutairi Fahad N
Published: September 2023

Herein, tin(II) 2,3-naphthalocyanine (SnNC) organic dye was successfully thermally deposited onto different optical transparent substrates such as glass, quartz, ITO, and FTO. FE-SEM technique reveals that SnNC film shows a uniform and symmetrical spherical-shaped with an average diameter of ∼50 nm. Annealing up to 473 K for 4 h increases the crystallite size of SnNC thin film. SnNC thin film shows absorption bands centered at 858 nm, 313 nm, and 249 nm with two shoulders at 775 nm and 350 nm. We present the absorbance, specular transmittance, specular reflectance and fluorescence properties of SnNc deposited on the different transparent substrates. The oscillator strengths (f) and the electric dipole strength (q2) of SnNC thin film were estimated from the molar absorptivity (

ε

molar

) spectra. According to the Tauc model, two optical gap transitions were estimated as 1.03 eV and 3.48 eV. Annealing up to 473 K for 4 h slightly increases them to 1.15 eV and 3.59 eV, respectively. At excitation wavelength = 360 nm, two emission bands were observed at around 403 nm and 674 nm. Upon annealing at 373 K and 473 K, the real part of the refractive index of SnNC thin film decreases, which is correlated with a decrease in mass density. Electrochemical HOMO—LUMO band gaps of SnNC estimated from the cyclic voltammetry (CV) measurements (

E

g

C
V

=
1.12

eV

) agree well with the observed optical energy gap estimated from the optical measurements. The wide range absorption, emission, good thermal stability, suitable optical band gap, and electrochemical properties, prove an effective example of organic dye suitable for organic electronic applications.
Spectral properties and exact solutions for Rabi-coupled noninteracting fermions in a spin-dependent anharmonic trapping potential
Authors: Xie Qiongtao
Published: September 2023

We investigate the effect of spin-motion coupling on the spectral properties of Rabi-coupled noninteracting fermions in a spin-dependent harmonic trapping potential plus an anharmonic term. It is shown that when the spin-motion coupling becomes strong, fermions tend to stay in one of the two components. In the limit of the strong spin-motion coupling, the entire energy spectrum exhibits a sequence of near degeneracy. In particular, in the case of the sextic anharmonic term, the system admits the exact analytical energies and wave functions of the bound states for an infinite number of the specific parameter conditions. The properties of the energy spectrum have also been discussed on basis of these obtained exact analytical solutions.
Ab initio investigations on the structural and optical properties of sol-gel synthesized bismuth telluride nanoparticles
Authors: T Rasmi , K A Malini
Published: September 2023

Bismuth telluride nanopowders are prepared by a simple but efficient wet chemical synthesis route namely Sol-gel auto-combustion. X-ray diffraction (XRD) and Scanning Electron Microscopic (SEM) analyses were used to study the structural and morphological characteristics. The crystallinity of the produced samples were verified using XRD, and composition was confirmed by Energy Dispersive x-ray analysis (EDAX) measurements. The optical characterization of the prepared bismuth nanopowders were also carried out using Diffused Reflectance Spectroscopy (DRS) and Raman spectroscopic analysis. The optical bandgap of the prepared nanopowder is found to be 3.27 eV. Raman active modes of the sample are also reported. The optical properties of the Bismuth telluride nanopowder are rarely reported. The optical constant evaluation of the prepared sample point towards the probable application of these materials in optoelectronic devices in addition to its conventional thermoelectric applications.
Ultraviolet-complete quantum field theories with fractional operators
Authors: Calcagni Gianluca , Rachwał Lesław
Published: September 2023

We explore quantum field theories with fractional d'Alembertian □
γ
. Both a scalar field theory with a derivative-dependent potential and gauge theory are super-renormalizable for a fractional power 1 < γ ≤ 2, one-loop super-renormalizable for γ > 2 and finite if one introduces killer operators. Unitarity is achieved by splitting the kinetic term into the product of massive fractional operators, eventually sending the masses to zero if so desired. Fractional quantum gravity is also discussed and found to be super-renormalizable for 2 < γ ≤ 4 and one-loop super-renormalizable for γ > 4. To make it unitary, we combine the splitting procedure with a fractional generalization of the Anselmi-Piva procedure for fakeons. Among new technical results with wider applications, we highlight the Leibniz rule for arbitrary powers of the d'Alembertian and the Källén-Lehmann representation for a propagator with an arbitrary number of branch cuts.
Superfluid dark matter in tension with weak gravitational lensing data
Authors: Mistele T. , McGaugh S. , Hossenfelder S.
Published: September 2023

Superfluid dark matter (SFDM) is a model that promises to reproduce the successes of both particle dark matter on cosmological scales and those of Modified Newtonian Dynamics (MOND) on galactic scales.
SFDM reproduces MOND only up to a certain distance from the galactic center, and only for kinematic observables: it does not affect trajectories of light.
We test whether this is consistent with a recent analysis of weak gravitational lensing that has probed accelerations around galaxies to unprecedentedly large radii. This analysis found the data to be close to the prediction of MOND, suggesting they might be difficult to fit with SFDM.
To investigate this matter, we solved the equations of motion of the model and compared the result to observational data.
Our results show that the SFDM model is incompatible with the weak-lensing observations, at least in its current form.
Primordial black holes and stochastic inflation beyond slow roll. Part I. Noise matrix elements
Authors: Mishra Swagat S. , Copeland Edmund J. , Green Anne M.
Published: September 2023

Primordial Black Holes (PBHs) may form in the early Universe, from the gravitational collapse of large density perturbations, generated by large quantum fluctuations during inflation. Since PBHs form from rare over-densities, their abundance is sensitive to the tail of the primordial probability distribution function (PDF) of the perturbations. It is therefore important to calculate the full PDF of the perturbations, which can be done non-perturbatively using the `stochastic inflation' framework. In single field inflation models generating large enough perturbations to produce an interesting abundance of PBHs requires violation of slow roll. It is therefore necessary to extend the stochastic inflation formalism beyond slow roll. A crucial ingredient for this are the stochastic noise matrix elements of the inflaton potential. We carry out analytical and numerical calculations of these matrix elements for a potential with a feature which violates slow roll and produces large, potentially PBH generating, perturbations. We find that the transition to an ultra slow-roll phase results in the momentum induced noise terms becoming larger than the field noise whilst each of them falls exponentially for a few e-folds. The noise terms then start rising with their original order restored, before approaching constant values which depend on the nature of the slow roll parameters in the post transition epoch. This will significantly impact the quantum diffusion of the coarse-grained inflaton field, and hence the PDF of the perturbations and the PBH mass fraction.
Testing BSM physics with gravitational waves
Authors: Muia F. , Quevedo F. , Schachner A. , Villa G.
Published: September 2023

The Cosmic Gravitational Wave Background (CGWB) is an irreducible background of gravitational waves generated by particle exchange in the early Universe plasma. Standard Model particles contribute to such a stochastic background with a peak at f∼80 GHz. Any physics beyond the Standard Model (BSM) may modify the CGWB spectrum, making it a potential testing ground for BSM physics.
We consider the impact of general BSM scenarios on the CGWB, including an arbitrary number of hidden sectors.
We find that the largest amplitude of the CGWB comes from the sector that dominates the energy density after reheating and confirm the dominance of the SM for standard cosmological histories.
For non-standard cosmological histories, such as those with a stiff equation of state ω > 1/3, like in kination, BSM physics may dominate and modify the spectrum substantially.
We conclude that, if the CGWB is detected at lower frequencies and amplitudes compared to that of the SM, it will hint at extra massive degrees of freedom or hidden sectors.
If it is instead measured at higher values, it will imply a period with ω > 1/3.
We argue that for scenarios with periods of kination in the early Universe, a significant fraction of the parameter space can be ruled out from dark radiation bounds at BBN.
Why is zero spatial curvature special?
Authors: Jimenez Raul , Khalifeh Ali Rida , Litim Daniel F. , Matarrese Sabino , Wandelt Benjamin D.
Published: September 2023

Evidence for almost spatial flatness of the Universe has been provided from several observational probes, including the Cosmic Microwave Background (CMB) and Baryon Acoustic Oscillations (BAO) from galaxy clustering data. However, other than inflation, and in this case only in the limit of infinite time, there is no strong a priori motivation for a spatially flat Universe. Using the renormalization group (RG) technique in curved spacetime, we present in this work a theoretical motivation for spatial flatness. Starting from a general spacetime, the first step of the RG, coarse-graining, gives a Friedmann-Lemaître-Robertson-Walker (FLRW) metric with a set of parameters. Then, we study the rescaling properties of the curvature parameter, and find that zero spatial curvature of the FLRW metric is singled out as the unique scale-free, non-singular background for cosmological perturbations.
Production rates of dark photons and Z' in the Sun and
stellar cooling bounds
Authors: Li Shao-Ping , Xu Xun-Jie
Published: September 2023

Light weakly interacting particles could be copiously
produced in the Sun which, as a well-understood star, could provide
severe constraints on such new physics. In this work, we calculate
the solar production rates of light gauge bosons (e.g. dark photon)
arising from various U(1) extensions of the standard model. It
is known that the dark photon production rate is suppressed by the
dark photon mass if it is well below the plasmon mass of the medium.
We show that for more general U(1) gauge bosons, this suppression
is absent if the couplings are not in alignment with those of the
photon. We investigate a few frequently discussed U(1) models including
 B - L, Lμ - Lτ
, and Le - Lμ(τ)
, and derive
the stellar cooling bounds for these models.
Progress on two-dimensional ferrovalley materials
Authors: Li 李 Ping 平 , Liu 刘 Bang 邦 , Chen 陈 Shuai 帅 , Zhang 张 Wei-Xi 蔚曦 , Guo 郭 Zhi-Xin 志新
Published: September 2023

The electron’s charge and spin degrees of freedom are at the core of modern electronic devices. With the in-depth investigation of two-dimensional materials, another degree of freedom, valley, has also attracted tremendous research interest. The intrinsic spontaneous valley polarization in two-dimensional magnetic systems, ferrovalley material, provides convenience for detecting and modulating the valley. In this review, we first introduce the development of valleytronics. Then, the valley polarization forms by the p-, d-, and f-orbit that are discussed. Following, we discuss the investigation progress of modulating the valley polarization of two-dimensional ferrovalley materials by multiple physical fields, such as electric, stacking mode, strain, and interface. Finally, we look forward to the future developments of valleytronics.
Optical spectrum of ferrovalley materials: A case study of Janus H-VSSe
Authors: Luo 罗 Chao-Bo 朝波 , Liu 刘 Wen-Chao 文超 , Peng 彭 Xiang-Yang 向阳
Published: September 2023

As opposed to the prototypical MoS2 with centroasymmetry, Janus ferrovalley materials such as H-VSSe are less symmetric with the mirror symmetry and time reversal symmetry broken, and hence possess spontaneous valley polarization and strong ferroelasticity. The optical transition is an important means to excite the valley carriers. We investigate the optical spectrum of H-VSSe by using the many-body perturbation-based GW approach and solving the Bethe–Salpeter equation (BSE) to include the electron–hole interactions. It is found that after the GW correction, the band gaps of the quasiparticle bands are much larger than those obtained by the normal density functional theory. The system is ferromagnetic and the valley gaps become non-degenerate due to spin–orbit coupling (SOC). The position of the lowest BSE peak is much lower than the quasiparticle band gap, indicating that the excitonic effect is large. The peak is split into two peaks by the SOC. The binding energy difference between these two BSE peaks is about the same as the difference between the inequivalent valley gaps. Our results show that in Janus H-VSSe the two lowest exciton peaks are from the two inequivalent valleys with different gaps, in contrast to the A and B exciton peaks of MoS2 which are from the same valley.
Direct Ion Beam Figuring Process and Rotational Measurement Method for Ultra-smooth Aspherical Surfaces of a 46.5 nm Telescope
Authors: Gu Weichen , Yu Jun , Sheng Pengfeng , Wu Qiaoyu , Huang Qiushi , Wang Zhanshan
Published: September 2023

This paper describes a fabrication process for the hyperboloidal concave mirror of a 46.5 nm telescope. The 180 mm aperture hyperboloidal concave mirror and 70 mm aperture compensator are machined directly from chemical mechanical polishing of a spherical surface to a high-accuracy aspherical surface by ion beam figuring. The aspherical measurement method is the Dall null test. To minimize system errors in the measurement process, the rotational measurement method with six rotations is used in the null test. The results of the analysis for the ME (first solve the machined surface profile, then solve the system errors) and EM (first solve the system errors, then solve the machined surface profile) methods of calculation in the measurement are given. The ME method is a more accurate rotational test method, and the six rotations are appropriate for rotational measurements. After the figuring process, the hyperboloidal concave mirror surface profile reached 8.27 nm rms and the compensator surface profile is approximately 4 nm rms. The roughness of the hyperboloidal concave mirror is smooth to 0.160 nm rms.
Numerical analysis of graphene oxide modified glass fiber/epoxy resin composites
Authors: Ni Xuweilai , Zhu Chenyang , Chen Long
Published: September 2023

Graphene is extensively used as a functional material due to its superb heat transfer and electrical conductivity properties. In this paper, sample graphene oxide /glass fiber/epoxy resin composites were prepared by ultrasonic decentralization. The heat transfer and stress distribution of the graphene-doped fiber-reinforced resin matrix composites were simulated by mathematical modelling. The reliability of the numerical heat transfer model is illustrated by comparing the measured temperature field distribution of the graphene oxide/glass fiber/epoxy composite samples with the numerical simulation results. It is also shown that graphene particles can facilitate heat transfer and the epoxy resin in the composite expands significantly more than the fibers, so the compressive stress on the fibers at the interface strengthens the bond between resin and fibers. Still, the thermal stress can cause the glass fiber ends to detach from the resin material and affect the material life.
Study on heat transfer failure time effect energy of lithium heat pipe
Authors: Zhang Yitong , Zhou Tao , Liu Wenbin , Wei Dong , Mao Shang , Xue Chunhui , Lu Huaichang , Yao Yao
Published: September 2023

Studying the efficiency of lithium heat pipe above 1000K in case of problems is of considerable value for mastering and controlling its safety. We use COMSOL software to model and calculate a single element above 1000 K, and calculate and analyze its various parameter changes under fault conditions. According to different situations that should be classified and discussed, the cold end fluid temperature and corresponding heat transfer coefficient in the lower temperature area, as well as the temperature situation at the other end, should be separately considered. Based on the calculated results, it is discussed that they all undergo linear and proportional changes with the target parameters, and the fluid situation on the lower temperature side has the smallest impact on these target results. The maximum temperature of the module will reach 1900K, and materials that can withstand 1900K need to be selected during design.
Cu2GeS3/Cd0.5Zn0.5S Heterojunction Thin Film Solar Cells
Authors: Bao Wujisiguleng , Qiu Fangyuan , Bai Sachuronggui
Published: September 2023

Ternary compounds such as Cu2GeS3(CGS) and Cu2SnS3(CTS) semiconductor materials have been considered as lower defects and environmentally friendly absorber layer materials for solar cells. In this work, the band offsets for CGS/CdS and CTS/CdS heterointerface are calculated by the first-principles calculation method. The valence band maximum (VBM) of CdS is below CGS (valence band offset ΔEV=1.4 eV), and the conduction band minimum (CBM) of CdS is below CGS (conduction band offset ΔEC=0.5 eV), i.e., the CGS/CdS is type II interface. The VBM of CdS is below CGS (ΔEV=1.4 eV), and the CBM of CdS is above CTS(ΔEC=-0.1 eV), i.e., the CTS/CdS heterojunction is type I. We also obtained the type I of CGS/Cd1−xZnxS heterointerface with a favorable barrier height of 0.2 eV by adjusting the composition of x in Cd1−xZnxS alloy with 0.5.
A Study on the Influencing Factors of the Compressive Strength of Planting Concrete
Authors: Liu Ying , Liu Dehua , Ma Lijie
Published: September 2023

It is a study on the influence of aggregate size, water-cement ratio, and target porosity on the compressive strength of planting porous concrete. Experiment results show that porous concrete’s compressive strength is negatively correlated with target porosity and aggregate size; no distinct linear relation with the water-cement ratio is indicated, and there is an optimal water-cement ratio in different mix proportions. Among the three factors influencing the compressive strength of porous concrete, target porosity ranks first in influence and is followed successively by aggregate size and water-cement ratio. Besides, the paste-coating method is helpful in the formation of connected pores of porous concrete.
Investigation on Rheological Characterization of Isotropic Conductive Adhesives
Authors: Li Saipeng , Jiang Qinglei , Wang Xuyan
Published: September 2023

In the field of microelectronic packaging technology, isotropic conductive adhesives (ICAs) have been used widely as interconnection materials between chips and substrates. ICAs are composed of silver powder particles and adhesive matrix. The paper analysed the rheological properties of ICAs at different temperatures in order to better apply ICAs in dispensing and jet printing processes. The viscosity, viscoelasticity, and thixotropic behaviours of ICAs were studied using various experimental methods such as oscillatory stress shear, and rotational rheology. The rheological behaviours of ICAs conforms to the Cross Model. In SAOS flow field, the ICAs has G”>G’ in LVR region, which shows the viscous component is dominant and ICAs represent viscoelastic fluid characteristics.
Influence of ultrasonic impact treatment on corrosion resistance of 7075 aluminum alloy welded joint
Authors: Ding BoSheng , He MingTao , Ma RongBin , Xie Li , Wang JiangTao , Zou ShengGuang , Liu Chang
Published: September 2023

To enhance the resist corrosion and service safety of 7075 aluminum alloy FSWed joints, an ultrasonic impact treatment was applied, and its effects on the surface morphology, microhardness, residual stress, and corrosion performance of the welded joint were investigated. The experimental results showed that after impact, the surface of the welded joint exhibited larger undulations. The distribution trend of micro-hardness changed from a “W” distribution to a uniform distribution, and the tensile residual stress (TRS) on the surface of the welded joint transformed into compressive residual stress (CRS). After the ultrasonic impact treatment, only minimal pitting corrosion occurred on the welded joint, and the corrosion current density decreased, while the capacitance arc radius increased. The resist corrosion of the welded joints was ameliorated.
Synthesis and Characterization of a New In-based Metal Organic Framework
Authors: Feng Mengchu , Yu Xinyu
Published: September 2023

In this work, by meticulously selecting high-valence intermetallic ions and functional tetracarboxylic acid organic ligands, we had the opportunity to effectively develop a new metal-organic framework In-MOFs. Metal nodes in In-MOF are interestingly linked to organic ligands, and twisted decahedra behave as tetrahedra, producing a 3D
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topology. These structures have been investigated via SCXRD, PXRD, and Fourier transform infrared (FT-IR). In-MOF features two one-dimensional channels of varying diameters in the c-axis and b-axis directions, 17.4 Å × 4.2 Å and 17.3 Å× 7.5 Å, respectively, and possesses high solvent stability.
Study of the Effect of double slotted construction on motor slot torque
Authors: Yan Hongliang , Wu Yabin
Published: September 2023

To address the problem of vibration and noise caused by high slot torque of stacked-in permanent magnet synchronous motor, a motor model with a rectangular slot in the stator and curved slot in the rotor is proposed to analyze the variation of slot torque with the auxiliary slot parameter based on the analysis of slot torque, taking an 8-pole 36-slot built-in permanent magnet synchronous motor as an example. The modeling results display that the slot torque reduces and then increases with the change of incomplete groove parameters. The slot torque is weakened by 92.01% when the stator with a rectangular slot rotor with a curved slot.
Design and Fabrication of an Environment Simulation Test Bed for Deep-sea Laser Cladding
Authors: Zhang Yingying , Liu Jingxi , Dong Wenkui
Published: September 2023

The complicated deep-sea high-pressure environment poses a significant challenge for deep-sea laser cladding. To solve this problem, an environment simulation test bed for deep-sea laser cladding is developed in this paper. First, a principle of environment simulation testbed is proposed, which can provide high-pressure water for underwater laser cladding simulation experiments. Based on the principle design, the structure of the environment simulation test bed is modeled in three dimensions, which can carry out underwater laser cladding experiments. Then, the strength of the pressure chamber is analyzed by finite element simulation. Finally, the environment simulation test bed for deep-sea laser cladding is modularly manufactured and integrally packaged. The environment simulation test bed for deep-sea laser cladding can be directly applicable to simulate underwater laser cladding.