bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural determinants of protein kinase A essential for CFTR channel activation
Authors: Mihályi Csaba , Iordanov Iordan , Szollosi Andras , Csanády László
Published: November 2024

Cystic Fibrosis Transmembrane Conductance Regulator (CFTR), the anion channel mutated in cystic fibrosis (CF) patients, is activated by the catalytic subunit of protein kinase A (PKA-C). PKA-C activates CFTR both noncatalytically, through binding, and catalytically, through phosphorylation of multiple serines in CFTR’s regulatory (R) domain. Here, we identify key molecular determinants of the CFTR/PKA-C interaction essential for these processes. By comparing CFTR current activation in the presence of ATP or an ATP analog unsuitable for phosphotransfer, as well as pseudosubstrate peptides of various lengths, we identify two distinct specific regions of the PKA-C surface which interact with CFTR to cause noncatalytic and catalytic CFTR stimulation, respectively. Whereas the “substrate site” mediates CFTR phosphorylation, a distinct hydrophobic patch (the “docking site”) is responsible for noncatalytic CFTR activation, achieved by stabilizing the R domain in a “released” conformation permissive to channel gating. Furthermore, by comparing PKA-C variants with different posttranslational modification patterns, we find that direct membrane tethering of the kinase through its N-terminal myristoyl group is an unappreciated fundamental requirement for CFTR activation: PKA-C demyristoylation abolishes noncatalytic, and profoundly slows catalytic, CFTR stimulation. For the F508del CFTR mutant, present in ~90% of CF patients, maximal activation by demyristoylated PKA-C is reduced by ~10-fold compared to that by myristoylated PKA-C. Finally, in bacterial genera that contain common CF pathogens, we identify virulence factors that demyristoylate PKA-C in vitro, raising the possibility that during recurrent bacterial infections in CF patients, PKA-C demyristoylation may contribute to the exacerbation of lung disease.
The structures of protein kinase A in complex with CFTR: Mechanisms of phosphorylation and noncatalytic activation
Authors: Fiedorczuk Karol , Iordanov Iordan , Mihályi Csaba , Szollosi Andras , Csanády László , Chen Jue
Published: November 2024

Protein kinase A (PKA) is a key regulator of cellular functions by selectively phosphorylating numerous substrates, including ion channels, enzymes, and transcription factors. It has long served as a model system for understanding the eukaryotic kinases. Using cryoelectron microscopy, we present complex structures of the PKA catalytic subunit (PKA-C) bound to a full-length protein substrate, the cystic fibrosis transmembrane conductance regulator (CFTR)—an ion channel vital to human health. CFTR gating requires phosphorylation of its regulatory (R) domain. Unphosphorylated CFTR engages PKA-C at two locations, establishing two “catalytic stations” near to, but not directly involving, the R domain. This configuration, coupled with the conformational flexibility of the R domain, permits transient interactions of the eleven spatially separated phosphorylation sites. Furthermore, we determined two structures of the open-pore CFTR stabilized by PKA-C, providing a molecular basis to understand how PKA-C stimulates CFTR currents even in the absence of phosphorylation.
Measuring diversity in Hollywood through the large-scale computational analysis of film
Authors: Bamman David , Samberg Rachael , So Richard Jean , Zhou Naitian
Published: November 2024

Movies are a massively popular and influential form of media, but their computational study at scale has largely been off-limits to researchers in the United States due to the Digital Millennium Copyright Act. In this work, we illustrate use of a new regulatory framework to enable computational research on film that permits circumvention of technological protection measures on digital video discs (DVDs). We use this exemption to legally digitize a collection of 2,307 films representing the top 50 movies by U.S. box office over the period 1980 to 2022, along with award nominees. We design a computational pipeline for measuring the representation of gender and race/ethnicity in film, drawing on computer vision models for recognizing actors and human perceptions of gender and race/ethnicity. Doing so allows us to learn substantive facts about representation and diversity in Hollywood over this period, confirming earlier studies that see an increase in diversity over the past decade, while allowing us to use computational methods to uncover a range of ad hoc analytical findings. Our work illustrates the affordances of the data-driven analysis of film at a large scale.
Path dependence, stigmergy, and memetic reification in the formation of the 27 Club myth
Authors: Dunivin Zackary Okun , Kaminski Patrick
Published: November 2024

The “27 Club” refers to the widespread legend that notable people, particularly musicians, are unusually likely to die at age 27. A 2011 inquiry in The BMJ showed this is not the case, dismissing the 27 Club as a myth. We expand on this discourse by demonstrating that although the existence of the phenomenon cannot be empirically validated, it is real in its consequences. Using Wikipedia data, we show that while age 27 does not hold greater risk of mortality for notable persons, those who died at 27 are as a group exceptionally notable compared to those who died at other young ages. The 27 Club legend originated from a statistically improbable event circa 1970, wherein four superstar musicians died within the span of 2 y all at age 27. This coincidence captured the public imagination such that our fascination with the 27 Club brought itself into being, producing greater interest in those who died at age 27 than would have been otherwise. This demonstrates path dependence in cultural evolution, whereby an effectively random event evolves into a narrative that shapes otherwise unrelated events and thus the way we make and interpret history.
Soft matter mechanics of baseball’s Rubbing Mud
Authors: Pradeep Shravan , Chen Xiangyu , Seiphoori Ali , Vann David R. , Arratia Paulo E. , Jerolmack Douglas J.
Published: November 2024

Researchers looking for sustainable materials with optimal mechanical properties may draw inspiration from a baseball tradition. For nearly 100 y, a mysterious mud harvested from an undisclosed river site in New Jersey (USA) has been the agent of choice in the USA’s Major League Baseball for “de-glossing” new baseballs. It is unclear, however, what makes this “Rubbing Mud” work. Here, we perform a multiscale investigation of the rheology and tribology of this mud material under baseball-relevant conditions and identify three mechanisms by which the mud alters the surface properties of the baseball. First, the mud creates a more uniform baseball surface by filling in pores in the leather; this is possible because of its relatively high cohesion (clays and organics) making the material remarkably shear thinning. Second, the residue of cohesive particles coating the baseball effectively doubles contact adhesion. Third, a sparse population of angular sand grains are bonded to the baseball by clay-sized particles, leaving a studded surface that enhances friction. The proportions of cohesive, frictional, and viscous elements in Rubbing Mud conspire to create a soft material with an unusual mix of properties, that could find other applications in the development of sustainable geomaterials. Our improved understanding of the flow and friction of natural muds may also find use in modeling natural hazards such as mudslides and for locomotion in muddy environments.
h-BN-assisted Metal Contact Transfer to InSe for Two-Dimensional Multifunctional Electronic Devices
Authors: Wei 尉 Chijun 驰俊 , Jiazila 努 Nuertai 尔泰·加孜拉 , Liu 刘 Xuanye 轩冶 , Song 宋 Peng 鹏 , Gao 高 Hui 辉 , Sun 孙 Jiequn 杰群 , Bao 鲍 Lihong 丽宏 , Lin 林 Xiao 晓 , Gao 高 Hong-Jun 鸿钧
Published: November 2024

Metal contacts to two-dimensional (2D) semiconductors are crucial for determining the electrical performance of electronic devices. However, traditional three-dimensional metal deposition processes cause damage to 2D semiconductors and considerable Fermi-level-pinning effects. In this study, a hexagonal boron nitride (h-BN)-assisted transfer method was proposed for transferring metal contacts to few-layered InSe for fabricating 2D functional electronic devices. Using the transferred Pt electrodes as the contact, p-type dominated ambipolar conduction behavior with the hole Schottky barrier height (SBH) approaching 0 meV was observed in field-effect transistors (FETs) comprising multilayered InSe. Based on this phenomenon, several InSe homojunctions were fabricated using a dual-gate modulating method such as p–p, n–n, p–n, and n–p. For InSe p–n homojunctions, a current rectification ratio of over 104 and optoelectronic detection capabilities were achieved. Furthermore, a complementary metal–oxide–semiconductor (CMOS) inverter with an ultra-high voltage gain exceeding 60 at V
DD = −1 V was fabricated. The proposed h-BN-assisted metal contact transfer method can be easily extended to other 2D semiconductors for fabricating complementary electronic and optoelectronic devices.
Effective Lifshitz black holes, hydrodynamics, and transport coefficients in fluid/gravity correspondence
Authors: Moreira D C , da Rocha R
Published: November 2024

Effective Lifshitz black holes with arbitrary dynamical exponent are addressed in the fluid/gravity membrane paradigm. The transport and the response coefficients in the dual Lifshitz field theory are calculated and analyzed, including the charge diffusion constant and the shear mode damping constant, along with the shear-viscosity-to-entropy density ratio. The Kubo formula is employed to obtain the electrical DC conductivity for the gauge sector corresponding to impurity through the holographic linear response of gauge vector fluctuations in the Lifshitz black brane geometry.
Existence and absence of Killing horizons in static solutions with symmetries
Authors: Maeda Hideki , Martínez Cristián
Published: November 2024

Without specifying a matter field nor imposing energy conditions, we study Killing horizons in

n
(
⩾
3
)

-dimensional static solutions in general relativity with an

(
n
−
2
)

-dimensional Einstein base manifold. Assuming linear relations

p

r

≃

χ

r

ρ

and

p
2

≃

χ

t

ρ

near a Killing horizon between the energy density ρ, radial pressure

p

r

, and tangential pressure p
2 of the matter field, we prove that any non-vacuum solution satisfying

χ

r

<
−
1

/

3

(

χ

r

≠
−
1

) or

χ

r

>
0

does not admit a horizon as it becomes a curvature singularity. For

χ

r

=
−
1

and

χ

r

∈
[
−
1

/

3
,
0
)

, non-vacuum solutions admit Killing horizons, on which there exists a matter field only for

χ

r

=
−
1

and

−
1

/

3

, which are of the Hawking–Ellis type I and type II, respectively. Differentiability of the metric on the horizon depends on the value of

χ

r

, and non-analytic extensions beyond the horizon are allowed for

χ

r

∈
[
−
1

/

3
,
0
)

. In particular, solutions can be attached to the Schwarzschild–Tangherlini-type vacuum solution at the Killing horizon in at least a

C

1
,
1

regular manner without a lightlike thin shell. We generalize some of those results in Lovelock gravity with a maximally symmetric base manifold.
Facilitating martensitic reorientation via porous structure of Ti-doped Ni–Mn–Ga shape memory alloy
Authors: Wang Kunyu , Wang Zhiqiang , Li Yunlong , Zhu Jie , Ding Zhiyi
Published: November 2024

Porous Ni–Mn–Ga shape memory alloy with the pore size of 20–30 μm was fabricated by the powder metallurgy with the pore-forming agent of NaCl. The prepared alloy has a uniform pore distribution and a complete sintering neck, which reduces the number of grain boundaries. Pores constrain the transmission of stress, leading to stress concentration, which decreases the critical stress of martensitic twin variants reorientation (<10 MPa). Meanwhile, the strength of porous alloys can be tuned by the alloying of Ti. In addition, the porous Ni–Mn–Ga alloy obtained a lower critical stress for martensitic twin boundary motion after cyclic compression, which makes it suitable for devices that require energy absorption under low stress. The microstructure and mechanical properties of Ni–Mn–Ga porous alloy were analyzed, and the effects of pores on the Ni–Mn–Ga alloy were also discussed.
Monolayer M2X2O as potential 2D altermagnets and half-metals: a first principles study
Authors: Zou Kaixin , Yang Yuxin , Xin Baojuan , Wu Wentao , Cheng Yahui , Dong Hong , Liu Hui , Luo Feng , Lu Feng , Wang Wei-Hua
Published: November 2024

Realizing novel two-dimensional (2D) magnetic states would accelerate the development of advanced spintronic devices and the understandings of 2D magnetic physics. In this paper, we have examined the magnetic and electronic properties of 20 dynamically stable and exfoliable M2X2O (M = Ti–Ni; X = S–Te; excluding Co2Te2O). It has been unveiled that [X4O2]-D
2h
and [M4]-D
4h
crystal fields govern the M-3d orbital splittings in M2X2O. The splittings further lead to the antiferromagnetic (AFM) orderings in Ti2S2O/Fe2S2O/Fe2Se2O/M2X2O (M = V, Cr, Mn and Ni; X = S–Se) as well as the ferromagnetic orderings in Ti2Se2O/Ti2Te2O/Fe2Te2O/Co2S2O/Co2Se2O through kinetic and superexchange mechanisms. Notably, all the AFM M2X2O are 2D altermagnets, and Ti2Se2O/Ti2Te2O/Co2S2O/Co2Se2O are 2D half-metals. In particular, the anisotropic d-d/p hoppings lead to the tunable altermagnetic splitting in Ti2S2O/Cr2Te2O, while the parity of V-3dyz
orbital contributes to the symmetry-protected altermagnetic splitting within V2X2O. These altermagnetic and half-metallic monolayer M2X2O provide promising candidates applied in low-dimensional spintronic devices. In addition, the potential 2D altermagnetic Weyl semimetal of Fe2S2O/Fe2Se2O, nodal-loop half-metal of Ti2Se2O and half-semi metal of Ti2Te2O facilitate to uncover novel low-dimensional topological physics. These theoretical results would expand the platform in particular for 2D altermagnets and nontrivial systems.
Controllable p-type doping and improved conductance of few-layer WSe2 via Lewis acid
Authors: Li Mengge , Ou Tianjian , Xiao Cong , Qiu Zhanjie , Wu Xiaoxiang , Guo Wenxuan , Zheng Yuan , Yang Hancheng , Wang Yewu
Published: November 2024

Manipulation of the electronic properties of layered transition-metal dichalcogenides (TMDs) is of fundamental significance for a wide range of electronic and optoelectronic applications. Surface charge transfer doping is considered to be a powerful technique to regulate the carrier density of TMDs. Herein, the controllable p-type surface modification of few-layer WSe2 by FeCl3 Lewis acid with different doping concentrations have been achieved. Effective hole doping of WSe2 has been demonstrated using Raman spectra and XPS. Transport properties indicated the p-type FeCl3 surface functionalization significantly increased the hole concentration with 1.2 × 1013 cm−2, resulting in 6 orders of magnitude improvement for the conductance of FeCl3-modified WSe2 compared with pristine WSe2. This work provides a promising approach and facilitate the further advancement of TMDs in electronic and optoelectronic applications.
Investigations on thermal and mechanical characteristics of PDMS embedded FBG sensors for wearable sensing applications
Authors: Chalackal Archana Thrikkaikuth , Kanakambaran Srijith
Published: November 2024

Fiber Bragg Grating (FBG) sensors embedded in polydimethylsiloxane (PDMS) are suitable for real-time monitoring of parameters like strain, temperature, force etc. This work investigates the thermal and mechanical properties of PDMS samples at mixing ratios of 6:1, 10:1, and 15:1 with embedded FBGs. The 10:1 sample showed the highest temperature sensitivity of 22.51 ± 0.54 pm ∘C−1. Young’s modulus values from mechanical characterization ranged from 2.20–8.16 MPa, 2.56–7.68 MPa, and 0.44–5.02 MPa for mixing ratios 6:1, 10:1, and 15:1, respectively. The highest force and strain sensitivities were 1.356 nm N−1 and 0.153 pm/µε for the 10:1 ratio, making it preferable for wearable sensors.
Novel family of probability generating distributions: Properties and data analysis
Authors: Ahmad Aijaz , Tashkandy Yusra , Rather Aafaq A , Bakr M E , Hussam Eslam , Gemeay Ahmed M
Published: November 2024

Current probability distributions often fall short when modeling lifespan data with non-monotonic hazard rate shapes, highlighting a gap in probability theory. To address this issue, this study introduces the novel family of probability-generating distributions (NP-G) as a solution to capture complex data patterns better. This research aims to develop and validate the NP-G distributions, which include a two-parameter continuous model based on the Weibull distribution. The study extensively explores the mathematical properties of the NP-G distributions, including series expansions of probability density functions, and evaluates various probabilistic measures such as moments, stress strength, mean deviations, entropy measures, and order statistics. Using the maximum likelihood method for parameter estimation and conducting a numerical simulation analysis, the study assesses the performance of the proposed extended exponentiated Weibull model. The findings demonstrate that this new model offers superior fit and accuracy compared to existing distributions when applied to two referenced datasets. This advancement is significant as it provides a more effective tool for analyzing lifespan data with non-monotonic hazard rates, enhancing both theoretical understanding and practical applications in fields such as reliability engineering and survival analysis.
Passively generated Q-switched pulses fiber laser in 2 μm wavelength using MXene Ti3C2Tx and Ti2CTx saturable absorber
Authors: Lip Zhan Hong , Cheng Xiau San , Chi Mingzhi , Sin Jin Tan , Abdul Latiff Anas , Harun Sulaiman Wadi
Published: November 2024

In this paper, Q-switched Thulium-doped fiber lasers (TDFLs) operating near the 2 μm region were demonstrated, utilizing a newly developed Thulium doped fiber as the gain medium and titanium carbide MXene as the saturable absorber (SA). The Thulium-doped fiber with a composition of SiO2-GeO2-Al2O3-HfO2-Y2O3-Bi2O3, was produced from a preform prepared using the modified chemical vapor deposition (MCVD) process. Two variations of titanium carbide MXene-based SA, Ti3C2Tx and Ti2CTx, were tested and compared, successfully generating Q-switched pulses. When Ti3C2Tx was used, the Q-switched pulse had a center wavelength of 1934.223 nm, a repetition rate of 55.39 kHz and a pulse width and 1.942 μs. For Ti2CTx, the generated Q-switched pulse has a center wavelength of 1932.229 nm, with a repetition rate of 77.28 kHz and a pulse width of 1.608 μs. The signal-to-noise ratio (SNR) values were 45.6 dB and 50.2 dB for Ti3C2Tx and Ti2CTx respectively. Based on the experimental results, both Ti3C2Tx and Ti2CTx show promise as SAs for generating Q-switched pulses in the 2 μm region within the TDFL cavity.
Decays Z → eaeb in a 3-3-1 model with neutral leptons
Authors: Hong T. T. , Hue L. T. , Phuong L. T. T. , Nha N. H. T. , Nguyen T. Phong
Published: November 2024

We investigate the 3-3-1 model with neutral leptons, a specific extension of the 3-3-1 models that includes heavy neutral leptons, which are sufficient to accommodate the neutrino oscillation data via the inverse seesaw mechanism. We will point out that this model can simultaneously explain the lepton flavor violating decays of the Z and Standard Model-like Higgs bosons into different charged leptons Z, h → e

a

e

b
, as well as the charged lepton decays e

b
→ e

a

γ, in agreement with the recent experimental data. In addition, the numerical results show strong correlations among the decay rates of the Z and h bosons predicted by this model. Specifically, some of these rates are nearly linearly dependent on each other. Consequently, the decay channels can be theoretically determined if one of them is detected in experiments.
Highly sensitive liquid level and temperature sensors based on all-fiber intermodal interferometers
Authors: Li Hongwei , Chen Qiang , Li Lida , Chen Hailiang , Li Shuguang , Ma Mingjian
Published: November 2024

Fiber optic-based precise measurements of liquid level and temperature are crucial for remote controlling in pharmaceutics, chemistry, and bromatology. Thus, it is essential to monitor liquid level and temperature simultaneously. In this paper, we propose all-fiber intermodal interferometers for highly sensitive liquid level and temperature measurements. We fabricated two different structures of single mode fiber-no core fiber-single mode fiber (SMF-NCF-SMF). One of them was used to measure the liquid level when the liquid soaked the NCF, and the other one was further coated with polydimethylsiloxane(PDMS) thermal-optic material and utilised to detect temperature. The measurement sensitivity of liquid level was 580 pm/mm within the range of 0–20 mm, while that of temperature was 1 nm/°C within the range of 28 °C–51 °C. A matrix was finally obtained by demodulating the measurements of liquid level and temperature. The proposed liquid level and temperature sensors, exhibiting the merits of high sensitivity, easy fabrication, and low cost, could be a candidate for precise and remote monitoring of liquid levels.
Study of isotropic stellar models via durgapal-lake solutions in rastall system
Authors: Waseem Arfa , Naeem Sunaiha
Published: November 2024

This manuscript is dealt with the influences of Rastall factor on the physical aspects of isotropic celestial models. In this scenario, both the ideal fluid distribution and static spherically symmetry are taken into consideration. In specifically, the Durgapal-Lake solutions are taken into consideration to analyze the different characteristics of several specific compact star models like Her X-1, Vela X-1, LMC X-4 and RXJ 1856-37. Due to its innovative combination of two methodologies, this solution is a significant advancement on Durgapal-Fuloria and Lake's previous ansatz in enormous crucial eras. Using observed estimates of radii and masses of certain specific star objects, the undefined parameters in Durgapal-Lake ansatz are derived by matching conditions. The consistency of the adopted solutions is examined through the visual interpretation of matter constituents, equation of state factor, energy conditions, mass function and stability criteria corresponding to distinct choices of Rastall factor. The radially symmetric graphs of matter variables as well as the mass function are also displayed. Moreover, We present the graphical analysis for vanishing Rastall factor. It is concluded that in the context of Rastall theory, the stars under examination exhibit stable compositions with Durgapal-Lake solution, while in the context of general relativity, they exhibit instability.
Single laser based novel wavelength shift keying scheme for ground to satellite bidirectional links
Authors: Faria  , Ghafoor Salman , Mirza Jawad , Aljohani Abdulah Jeza , Aziz Imran
Published: November 2024

Laser communication in space is gaining more recognition due to its ability to provide a much broader and unregulated data transmission capacity compared to traditional radio frequency systems, while also significantly decreasing the size, power requirements, and weight of the communication system. In this work, a novel technique for the generation of a wavelength shift keying (WSK) signal for the bidirectional transmission of 10 Gbps data between the ground station and low Earth orbit (LEO) satellite is presented. Our proposed scheme requires a single laser source to transmit WSK signal, that generally requires two wavelength sources to transmit the binary data bits. Furthermore, the scheme allows us to remodulate the optical signal received at the LEO satellite for downlink signal transmission. Therefore, the requirement of a laser source at the LEO satellite is eliminated, achieving the much desirable goals of low power consumption, weight and cost. The free space optical (FSO) channel is modelled using the gamma-gamma channel model. The performance of the proposed link is also compared with a conventional On-Off keying (OOK) based modulation scheme by using bit-error-rate (BER) as the performance metric.
A dynamic semi-quantum private comparison protocol for size relations
Authors: Ye Chong-Qiang , Chen Xiaoyu , Li Jian
Published: November 2024

Semi-quantum private comparison allows multiple ‘classical’ users who have restricted quantum capabilities to compare their private data with the assistance of a quantum third party. In this work, we propose a novel dynamic semi-quantum private comparison protocol using a circular transmission mode along with d-dimensional single-particle states. The protocol enables the comparison of data size relations among several ‘classical’ users, while the third party can only determine the relative sizes without accessing the users’ secret information. Security evaluations demonstrate that the designed protocol withstands typical external and internal attacks. Compared to previous works, this protocol offers several improvements: first, it supports dynamic addition or removal of users, enhancing applicability in practical scenarios; second, it eliminates the need for pre-shared keys, reducing quantum resource consumption; third, it avoids the use of high-dimensional multi-particle entangled states, thereby enhancing the feasibility of implementation. Therefore, the proposed protocol may have more practical potential compared to previous protocols.
Layout optimization and performance analysis of large array of imaging atmospheric Cherenkov telescopes*
Authors: Zhang 张 Zhipeng 志鹏 , Yang 杨 Ruizhi 睿智 , Zhang 张 Shoushan 寿山 , Xie 谢 Zhen 禛 , Liu 刘 Jiali 加丽 , Yin 尹 Liqiao 丽巧 , Wang 王 Yudong 玉东 , Ma 马 Lingling 玲玲 , Cao 曹 Zhen 臻
Published: November 2024

The large array of imaging atmospheric Cherenkov telescopes (LACT) is a planned array of 32 Cherenkov telescopes, each featuring 6-m diameter mirrors, to be constructed at the LHAASO site. This study focused on optimizing the array layout and analyzing the performance of LACT. Two observation modes were examined: large zenith angle observations for ultra-high energy events and small zenith angle observations for lower energy thresholds. For large zenith angles (60°), simulations indicate that an 8-telescope subarray can achieve an effective area of

with excellent angular resolution. For small zenith angles, we optimized the layout of 4-telescope cells and the full 32-telescope array. The energy threshold of the full array is approximately 200 GeV, which is particularly crucial for studying transient phenomena such as gamma-ray bursts (GRBs) and active galactic nuclei (AGNs). This study provides essential guidance for finalizing the LACT layout design and estimating performance under various observational conditions. It also highlights the potential of LACT for conducting deep observations of ultra-high energy
γ-ray sources, performing morphological studies of PeVatrons, and advancing time-domain
γ-ray astronomy.
Porous dielectric design for high-performance flexible shear sensors
Authors: Bu Yingxuan
Published: November 2024

Flexible sensors, renowned for their exceptional adaptability, are widely utilized in areas such as robotics and healthcare monitoring. Currently, understanding the relationship between the structure and performance of flexible shear sensors has become increasingly important. In this study, the structural characteristics of porous flexible shear sensors and their impact on performance were analyzed using Finite Element Method (FEM). The investigation focused on three factors: porosity, pore size, and the shape of elliptical pores. The findings suggest that augmenting the porosity substantially boosts the shear sensitivity of the sensor, whereas the pore size exerts a relatively minor influence on sensitivity. Furthermore, compared to circular ones, elliptical pores can further increase the shear sensitivity of the sensor, particularly when the ellipse’s major axis is oriented horizontally. These findings are of significant reference value for designing and optimizing high-performance flexible shear sensors.
Injection over-molding process of PEEK composites
Authors: Yang Yufan , Hu Nan , Wu Zijie , Hao Jie , Qiu Lili
Published: November 2024

This study utilizes experimental and microscopic characterization methods to investigate the prospects and feasibility of using the Injection Over-Molding (IOM) process to replace traditional adhesives in the manufacturing of complex ribbed panel structures with Polyether Ether Ketone (PEEK) composites. The results indicate that the IOM process can achieve the optimal bonding strength of adhesives while significantly reducing the processing cycle, demonstrating substantial potential. Additionally, enhancing the melt temperature and mold temperature can further improve interface bonding quality and increase bonding strength. Based on the experimental results, it is inferred that increasing the melt temperature can elevate the interface temperature while raising the mold temperature can slow down the interface cooling rate, suggesting mechanisms by which these parameters influence interface bonding quality.
A novel output window for dual-band gyrotron amplifier
Authors: Wang Xiaoyan , Fang Jinyong , Wu Jiangniu , Peng Kai
Published: November 2024

As a high-frequency, high-power, and high-bandwidth microwave source, the gyrotron amplifier has good application prospects in the aerospace field. The microwave window is of great significance for the high-frequency characteristics, power capacity, lifespan, and reliability of the gyrotron amplifier. This paper introduces a novel double-disk sapphire output window, which has excellent mechanical strength, high-temperature resistance, and high power capacity. The transmission coefficient S21 of TE01 mode is greater than −1 dB in 8.29 GHz∼9.73 GHz, and the S21 of TE02 mode is greater than −1 dB in 16.33 GHz −17.8 GHz, which can ensure wide bandwidth operation of high microwave transmission in X and Ku bands. It solves the problem of using one port to achieve microwave output in two bands for dual-band gyrotron amplifiers.
Design optimization of anti-spin parachute for fighter-class aircraft
Authors: Zhang Qi , Cheng Jiaao
Published: November 2024

In the absence of spin wind tunnel test and model free flight test support, the traditional empirical formulas had low accuracy and large dispersion, which made it difficult to effectively support the anti-spin parachute design of fighter planes. Based on the principle of spin motion, the empirical formula is modified from two aspects: aircraft aerodynamic layout and mass characteristics. At the same time, the relationship between the parachute area and the flight weight is summarized, which makes the estimated result closer to the actual value and more applicable. In addition, aiming at the problem of excessive load in the design of anti-spin parachutes, the causes of the problem are analyzed in detail. The design criterion of the anti-spin parachute is optimized. Under the premise of ensuring the recovery effect, the need to strengthen the aircraft body structure is effectively reduced. The results show that the engineering estimation methods and design criteria of the anti-spin parachute proposed in this paper are effective after simulation and actual application and can provide technical support for subsequent anti-spin parachute design of new fighter planes.
The effect of functional group of Graphene-based woven filter on the desalination performance
Authors: Huang Ziqi , Liang Lijun
Published: November 2024

Graphene-based braided filter membranes (GWFM) are becoming increasingly crucial in seawater desalination because of their excellent performance, moving from research to practical use and helping to tackle water scarcity. However, the mechanisms associated with GWFMs functionalized by functional groups are unclear. This paper demonstrates that graphene strips are intricately integrated into a filtration membrane characterized by X-functional groups (GWFM-X). Molecular dynamics (MD) simulations are effective for calculating water flux, assessing salt discharge effects, and understanding the physical mechanisms in seawater desalination, making them crucial for optimizing and advancing desalination technology and salt rejection rate of four types of GWFM-X, namely GWFM-1.2nm-COOH, GWFM-1.2nm-NH2, GWFM-1nm-COOH, and GWFM-1nm-NH2, which were designed with different functional groups and nanopore diameters. These results demonstrate the superior performance of GWFM-X in water filtration applications. Salt rejection efficiency of four distinct variants of GWFM-X, namely GWFM-1.2nm-COOH, GWFM-1.2nm-NH2, GWFM-1nm-COOH, and GWFM-1nm-NH2, is designed with different functional groups and nanopore diameters. The test membrane shows exceptional water flux, significantly outperforming current commercial reverse osmosis membranes, with measurements of 30.00±0.49 L cm−2 day−1 MPa−1, 35.41±0.71 L cm−2 day−1 MPa−1, 9.31±0.31 L cm−2 day−1 MPa−1, and 20.66±0.21 L cm−2 day−1 MPa−1, respectively. The free energy profiles of GWFM-X reveal a pronounced disparity in free energy barriers between water molecules and Na+/Cl− ions, with a difference of up to 14.26 kBT. The simulation results show that the seawater desalination system maintains over 75% efficiency at pressures between 10 and 500 MPa, highlighting its effectiveness and versatility. Moreover, advancements in nanofabrication technology are paving the way for new membrane materials that could improve desalination methods and help address water scarcity.
Preparation and performance study of a new solvent-free insulation coating for low-voltage busbar
Authors: Deng Xingyue
Published: November 2024

This study focuses on low-voltage busbar insulation and is committed to developing a new solvent-free insulation coating. A coating formula with specific properties was successfully synthesized by screening and optimizing various raw materials. A comprehensive and in-depth testing and analysis were conducted on the developed coatings’ physical properties, electrical insulation performance, heat resistance, and chemical corrosion resistance. The results show that the new solvent-free insulation coating has excellent heat resistance, corrosion resistance, and mechanical strength while maintaining good insulation performance. Compared with traditional insulation coatings, its solvent-free properties effectively reduce the emission of volatile organic compounds, meeting environmental requirements. This study provides a more efficient, reliable, and environmentally friendly solution for the insulation protection of the low-voltage busbar, which has significant practical application value and broad market prospects.
Material selection and design of intake blades for aircraft engines based on additive manufacturing
Authors: Hou Yibing , Luo Haocheng , Dong Siying
Published: November 2024

The intake blades of aircraft engines are mainly used to capture and guide external air into the engine and are the foundation of engine operation. Their materials and design are related to the performance level and reliability of the entire engine. The “additive” 3D printing manufacturing method has the advantages of high precision, low cost, less material waste, strong design, and a short research and development cycle. This article proposes the use of GH4169 high-temperature alloy as the 3D printing material for the service requirements of aircraft engine intake blades, constructs a 3D printing model, and designs and realizes the 3D printing of engine intake blades.
Experimental and numerical analysis of mechanics and fracture characteristics of engine compressor
Authors: Yu Guifeng , Guo Junfei , Wang Jinlong , Shi Zeyu , Du Fengming , Yang Yuxing
Published: November 2024

Investigating the fatigue failure behavior of compressor fan blades and their materials in aero-engines is a crucial research area. This paper focuses on the compressor fan blades and their constituent materials of aero-engines. Firstly, fluid-structure interaction (FSI) numerical simulations under various rotational speeds are conducted to determine the stress distribution and identify the maximum stress. Secondly, based on the FSI results, fatigue tests on fan blade materials under different stress amplitudes are performed to explore the relationship between load and life, so as to analyze the fracture characteristics under various stress amplitudes. This research has significant implications for ensuring the stable operation of aero-engine fan blades.
Application of PCA-LSTM algorithm in predicting component faults in CNC machining centers
Authors: Wang Shuwei
Published: November 2024

In order to further explore the relationship between component failures and CNC machining center failures, a method of predicting component failures in advance was proposed to reduce the likelihood of machining center failures and improve CNC machining efficiency. In this paper, the principal component analysis method is used to optimize the Long short-term memory neural network to build a network model to study and predict the fault status of NC machining center components in work. The use of Principal Component Analysis (PCA) to extract the main features of machine tool faults can improve the speed of iterative training networks during the machining process and reduce the input dimension and prediction difficulty of LSTM. The extracted data is used as input for the LSTM network. The fault type is output. The comparison of diagnostic results between PCA-LSTM, LSTM, and BP neural networks shows that PCA-LSTM is a high-precision prediction model. The root mean square difference is reduced to 1.572. The predicted error results can effectively reflect the changes that occur in the machining center components with the occurrence of faults. It can be seen that it is feasible to use PCA-LSTM as a tool for predicting the faults of CNC machining center components.
Experimental studies on the exhaust emissions of a n-butanol/diesel dual-fuel HCCI engine under different intake temperature
Authors: Song Jiantong , Zhu Chunhong , Shi Yuanfang , Fu Yiwei
Published: November 2024

To improve the exhaust emissions of n-butanol/diesel blends fueled HCCI engines, the influence of intake temperature (Tin) on the HC, CO, and NO
x
emissions was studied by bench tests on λ of 2.5, engine speed of 1000 r/min under the conditions with the blending ratio of B50 and B90. Experimental results show that the HC and CO decline as Tin rises. At the same Tin, the CO and HC of B90 are lower than B50. When the intake temperature is lower than 150°C, the NO
x
emissions are almost zero.
Numerical study on transonic shock wave buffeting of airfoil
Authors: Hu Zicheng , Zhu Liangchong , Mo Xin , Shen Keming
Published: November 2024

Modern transportation aircraft typically cruise at transonic speeds. However, under a specific combination of incoming flow Mach numbers and angles of attack, periodic self-excited oscillations of shock waves can lead to unsteady aerodynamic loads, causing sustained vibrations in the aircraft, which is known as transonic shock wave buffeting. Buffeting loads significantly impact the fatigue life of the aircraft’s structural materials and its handling performance. In severe cases, it causes structural damage or even leads to flight safety incidents, so we should pay more attention to transonic shock wave buffeting when focusing on aeronautical engineering. This paper employs computational fluid dynamics technology for calculations to solve the Navier-Stokes equations, using the SST k-ω turbulence model to numerically simulate the steady flow field, and further employing the detached eddy simulation (DES) method to study and analyze the buffeting initiation mechanism and flow field characteristics of the NACA0012 airfoil’s transonic unsteady flow. By applying the DES method, the results demonstrate an accurate prediction of the buffeting onset boundary of the airfoil compared to wind tunnel experimental data. The research findings on the initiation mechanism and load characteristics of transonic buffeting provide a theoretical basis for optimizing the aerodynamic performance of aircraft during transonic flight and offer guidance for engineering issues such as buffeting load mitigation.
Overall design and structural finite element analysis of deep-sea mining test device
Authors: Liu Jiancheng , Liu Jiwei , Li Lei , Rong Liangwan , Ma Yong
Published: November 2024

In order to support the experimental research and optimization of the deep-sea mining acquisition device, the overall design of a test device capable of carrying multiple acquisition heads was carried out. The design is divided into three parts: the bearing system of the device, the acquisition system, and the data collection system. It also includes the layout scheme of instruments and equipment such as flowmeter and pressure sensor. The experimental platform of simulation acquisition is constructed. The strength and stiffness of the main structure of each system are analyzed and optimized. The analysis results show that the strength and stiffness of the test device can meet the test requirements. The structural arrangement of the device meets the requirements of the test function, which provides a reference for the application design of similar devices.
Failure analysis on cracking and leakage of 304 stainless steel flange in petrochemical butyl device
Authors: Cheng Lei , Du Chenyang , Li Xiaowei , Liu Baolin , Cui Guoju
Published: November 2024

During the pressure test process in a petrochemical butyl device in China, it was found that the 304 stainless steel flange of the ethylene pipeline appeared to be cracking and leakage. This article analyzed the reasons for failure using macroscopic inspection, chemical composition analysis, metallographic structure analysis, scanning electron microscope, energy dispersive spectroscopy, mechanical properties test, and intergranular corrosion test. The results show that the carbon content of the flange base material exceeds the standard, many carbides precipitate at the grain boundary, the material itself is seriously sensitized, and the intergranular corrosion resistance is reduced. At the same time, under corrosive media such as sulfur and chlorine and high stress, the flange displays stress corrosion cracking, which leads to cracking and leakage failure. This article reports the reasons for the failure of the flange, and some reasonable suggestions are put forward to avoid similar leakage accidents.
Exploration of the damage evolution of HTPB propellant adhesive interface based on trilinear damage model
Authors: Jiang Pengchen , Li Chuntao , Xu Fangyi , Song Xiangyu , Li Wei
Published: November 2024

In this paper, the HTPB propellant was used as the research object. A uniaxial tensile test was carried out at four rates. A mesoscopic model of propellant was established using the molecular dynamics method. The trilinear cohesion model was used to describe the damage behavior of the particle/matrix interface, which revealed the damage evolution of HTPB propellant under different strain rates. The results show that the interfacial damage of HTPB propellant is diffused at a high strain rate, the damage degree is lower, and the number is higher at a lower strain rate. The method adopted in this paper can reasonably describe the damage evolution phenomenon of the adhesive interface of HTPB propellant.
Study on the bending mechanical properties of composite tube and metal joint bonding structure
Authors: Yan Liang , Xu He , Li Biao , Liu Dong , Lin Yongwen
Published: November 2024

The study of the mechanical properties of composite adhesively bonded joints is a very important issue, which directly affects the safety and reliability of the structure. This article studies the bending performance of carbon fiber composite tubes and metal joint bonding structures, as well as obtains the structural bearing capacity, influencing factors, and structural failure modes. Through mechanical analysis and static bending load tests, it is shown that the failure model of composite tube adhesively bonded metal joints under bending load is manifested as the first layer peeling or interlayer failure of the composite material in the bonding area between the tube and the joint, leading to local crushing at the end of the tube. There is no gap between the tube and the joint, which has little effect on the bending bearing capacity. The thickness gradient treatment at the end of the joint does not help improve the bending bearing capacity. The adhesive layer is at a 90 ° angle, which makes it easy for the first layer to peel off; it should be avoided. Other angle layers have little impact on load-bearing capacity. The longer the bonding length is, the stronger the bending capacity is. The adhesive J133 or 420 has a similar load-bearing. Wrapping a carbon fiber unidirectional layer around the ends of tubes and joints is helpful in improving their bending load-bearing capacity.
Space approaching assessment of SVOM satellite to other space objects
Authors: Li Dong , Jiang Hu , Zhang Xiaofeng , Su Ruifeng , He Junwang
Published: November 2024

The SVOM satellite is one of the joint space projects between China and France. It was successfully launched into the preferred orbit in June 2024. Its goal is to monitor the Gamma Ray Burst in space. The mission consists of 4 main instruments: ECLAIRs, MXT, GRM, and VT. The ECLAIRs telescope is used to detect and position gamma bursts in the X-ray band and low-energy gamma rays. Micro-channel X-ray Telescope (MXT telescope) will make the observation of gamma bursts in the soft X-ray range. GRM (Gamma Ray Burst Monitor) is used to measure the spectrum of high-energy bursts. VT telescope (Visible Telescope) operates in the visible range to detect and observe the visible emission produced immediately after a gamma burst. Based on recent orbit elements for the SVOM satellite, which was available via TT&C, SOCRATES Plus software is used to carry out space collision assessment for the SVOM satellite. SVOM and the accompanying satellite shared the same rocket before they were sent into their own preferred orbits. During the simulations, the mean main orbit elements are derived from the GNSS PV data sets, which can help to know the orbit health of SVOM. On June 27, 2024, the distance between SVOM and the accompanying satellite varies between 509 km and 620 km, and the distance between SVOM and the rocket residual varies between 441 km and 5263 km. On July 2, 2024, the distance between SVOM and the accompanying satellite varies between 1067 km and 1180 km, and the distance between SVOM and the rocket residual varies between 357 Km and 5107 Km. In addition, space approaching the SVOM satellite and other objects is simulated for five-day intervals; it turns out that there are three space objects approaching the SVOM satellite with about 4 km - 5 Km separation.
Research on load prediction of carrier-based aircraft landing test based on measured data
Authors: Xie Feng’an , Xu Whenchao
Published: November 2024

As one of the most important parts in the ground (carrier) landing process of carrier-based aircraft, undercarriage is directly related to the safety of the aircraft, the crew, and even the landing platform with its strength and stiffness. The landing test to evaluate the strength and stiffness of the undercarriage of the carrier-based aircraft has strict regulations on the sinking velocity of the aircraft during landing. Still, in consideration of safety, it is difficult for the aircraft to reach the sinking velocity specified in the test under normal conditions. In this thesis, based on a large number of measured flight data, the artificial neural network was used to reasonably predict the undercarriage landing load of carrier-based aircraft and improve the landing test points, thus providing a new idea for the research on undercarriage load strength.