bluuebunny/crossref_metadata_2025 huggingface dataset:
Laser beam properties and microfluidic confinement control thermocavitation
Authors: Schoppink Jelle J. , Alvarez-Chavez Jose A. , Fernandez Rivas David
Published: January 2024

Thermocavitation, the creation of a vapor bubble by heating a liquid with a continuous-wave laser, has been studied for a wide range of applications. Examples include the development of an actuator for needle-free jet injectors, as the pumping mechanism in microfluidic channels and nanoparticle synthesis. Optimal use in these applications requires control over the bubble dynamics through the laser power and beam radius. However, the influence of the laser beam radius on the bubble characteristics is not fully understood. Here, we present a way to control the beam radius from an optical fiber by changing the distance from the glass–liquid interface. We show that the increase in the beam size results in a longer nucleation time. Numerical simulations of the experiment show that the maximum temperature at nucleation is 237 ± 5 °C and independent of laser parameters. Delayed nucleation for larger beam sizes results in more absorbed energy by the liquid at the nucleation instant. Consequently, a larger beam size results in a faster growing bubble, producing the same effect as reducing the laser power. We conclude that the bubble energy only depends on the amount of absorbed optical energy and it is independent of the beam radius and laser power for any amount of absorbed energy. This effect contrasts with pulsed lasers, where an increase in the beam radius results in a reduction of bubble energy. Our results are of relevance for the use of continuous-wave laser-actuated cavitation in needle-free jet injectors as well as other applications of thermocavitation in microfluidic confinement.
Over 6 μm thick MOCVD-grown low-background carrier density (1015 cm−3) high-mobility (010) β-Ga2O3 drift layers
Authors: Bhattacharyya Arkka , Peterson Carl , Chanchaiworawit Kittamet , Roy Saurav , Liu Yizheng , Rebollo Steve , Krishnamoorthy Sriram
Published: January 2024

This work reports high carrier mobilities and growth rates simultaneously in low unintentionally doped (UID) (1015 cm−3) metalorganic chemical vapor deposition (MOCVD)-grown thick β-Ga2O3 epitaxial drift layers, with thicknesses reaching up to 6.3 μm, using triethylgallium (TEGa) as a precursor. Record-high room temperature Hall mobilities of 187–190 cm2/V s were measured for background carrier density values of 2.4–3.5 × 1015 cm−3 grown at a rate of 2.2 μm/h. A controlled background carrier density scaling from 3.3 × 1016 to 2.4 × 1015 cm−3 is demonstrated, without the use of intentional dopant gases such as silane, by controlling the growth rate and O2/TEGa ratio. Films show smooth surface morphologies of 0.8–3.8 nm RMS roughness for film thicknesses of 1.24–6.3 μm. Vertical Ni Schottky barrier diodes (SBDs) fabricated on UID MOCVD material were compared with those fabricated on hydride vapor phase epitaxy material, revealing superior material and device characteristics. MOCVD SBDs on a 6.3 μm thick epitaxial layer show a uniform charge vs depth profile of ∼ 2.4 × 1015 cm−3, an estimated μdrift of 132 cm2/V s, breakdown voltage (VBR) close to 1.2 kV, and a surface parallel plane field of 2.05 MV/cm without any electric field management—setting record-high parameters for any MOCVD-grown β-Ga2O3 vertical diode to date.
Photolysis characteristics and influencing factors of adenosine 5′-monophosphate in seawater
Authors: Cao Xiao-Yan , Liu Min , Li Ling , Yang Gui-Peng
Published: January 2024

Environmental context Organophosphorus (OP) is bioavailable to phytoplankton with photolysis can play an important role in the process. The photolysis behaviour of an OP (adenosine 5′-monophosphate, AMP) in seawater was investigated, and AMP can release inorganic phosphate under environmentally relevant light conditions, indicating OP photodegradation might be important in the phosphorus biogeochemical cycle. The results are helpful to further understand the bioavailability and cycle of OP in marine environment. Rationale Organic phosphorus (OP) is a potential source of bioavailable phosphorus for phytoplankton through photolysis and other degradation processes. Therefore, OP photodegradation plays an important role in phosphorus biogeochemical cycle. Methodology Taking adenosine 5′-monophosphate (AMP) as a model OP, we investigated the photolysis behaviour in seawater and discussed the mechanism. The photolysis dynamics were studied based on the inorganic phosphorus production at appropriate time intervals, which was analysed by spectrophotometric molybdenum blue method. The effects of medium, light and radicals were investigated. Results It was found that AMP can release inorganic phosphate under photosynthetically active radiation and ultraviolet (UV) with UVB being the most reactive band. The degradation of AMP in seawater was lower than that in deionised water under the same conditions, and the fresh seawater was more beneficial than aged seawater. The kinetics could be described by a pseudo-first order equation. Fe3+ can promote the photolysis due to the generation of ·OH radicals, while within the range of this study, changes of Fe3+ content have no substantial effect on the promotion. The influence of ethanol and tetrahydrofuran as radical inhibitor showed evident inhabitation to the degradation, indicating that ·OH and 1O2 played an important role in the process, and ·OH seemed more important than 1O2. Discussion OP photodegradation is of importance in the phosphorus biogeochemical cycle. Varying properties of the medium and light can affect the OP transformation in seawater. The results are helpful to further understand the bioavailability and cycle of OP in the marine environment.
Mechanistic basis for potassium efflux–driven activation of the human NLRP1 inflammasome
Authors: Rozario Pritisha , Pinilla Miriam , Gorse Leana , Vind Anna Constance , Robinson Kim S. , Toh Gee Ann , Firdaus Muhammad Jasrie , Martínez José Francisco , Kerk Swat Kim , Lin Zhewang , Chambers John C. , Bekker-Jensen Simon , Meunier Etienne , Zhong Franklin
Published: January 2024

Nigericin, an ionophore derived from
Streptomyces hygroscopicus
, is arguably the most commonly used tool compound to study the NLRP3 inflammasome. Recent findings, however, showed that nigericin also activates the NLRP1 inflammasome in human keratinocytes. In this study, we resolve the mechanistic basis of nigericin-driven NLRP1 inflammasome activation. In multiple nonhematopoietic cell types, nigericin rapidly and specifically inhibits the elongation stage of the ribosome cycle by depleting cytosolic potassium ions. This activates the ribotoxic stress response (RSR) sensor kinase ZAKα, p38, and JNK, as well as the hyperphosphorylation of the NLRP1 linker domain. As a result, nigericin-induced pyroptosis in human keratinocytes is blocked by extracellular potassium supplementation, ZAKα knockout, or pharmacologic inhibitors of ZAKα and p38 kinase activities. By surveying a panel of ionophores, we show that electroneutrality of ion movement is essential to activate ZAKα-driven RSR and a greater extent of K+ depletion is necessary to activate ZAKα-NLRP1 than NLRP3. These findings resolve the mechanism by which nigericin activates NLRP1 in nonhematopoietic cell types and demonstrate an unexpected connection between RSR, perturbations of potassium ion flux, and innate immunity.
Multifractality in spin glasses
Authors: Baity-Jesi Marco , Calore Enrico , Cruz Andrés , Fernández Luis Antonio , Gil-Narvión José Miguel , González-Adalid Pemartín Isidoro , Gordillo-Guerrero Antonio , Íñiguez David , Maiorano Andrea , Marinari Enzo , Martín-Mayor Víctor , Moreno-Gordo Javier , Muñoz Sudupe Antonio , Navarro Denis , Paga Ilaria , Parisi Giorgio , Pérez-Gaviro Sergio , Ricci-Tersenghi Federico , Ruiz-Lorenzo Juan Jesús , Schifano Sebastiano Fabio , Seoane Beatriz , Tarancón Alfonso , Yllanes David
Published: January 2024

We unveil the multifractal behavior of Ising spin glasses in their low-temperature phase. Using the Janus II custom-built supercomputer, the spin-glass correlation function is studied locally. Dramatic fluctuations are found when pairs of sites at the same distance are compared. The scaling of these fluctuations, as the spin-glass coherence length grows with time, is characterized through the computation of the singularity spectrum and its corresponding Legendre transform. A comparatively small number of site pairs controls the average correlation that governs the response to a magnetic field. We explain how this scenario of dramatic fluctuations (at length scales smaller than the coherence length) can be reconciled with the smooth, self-averaging behavior that has long been considered to describe spin-glass dynamics.
A Search for Radio Pulsars in Supernova Remnants Using FAST with One Pulsar Discovered
Authors: Zhang 张 Zhen 振 , Yan 闫 Wen-Ming 文明 , Yuan 袁 Jian-Ping 建平 , Wang 王 Na 娜 , Bai 白 Jun-Tao 俊涛 , Wen 温 Zhi-Gang 志刚 , Li 李 Bao-Da 保达 , Xie 解 Jin-Tao 进涛 , Zhao 赵 De 德 , Wang 王 Yu-Bin 榆斌 , Zhai 翟 Nan-Nan 楠楠
Published: January 2024

We report the results of a search for radio pulsars in five supernova remnants (SNRs) with the FAST telescope. The observations were made using the 19-beam receiver in “snapshot” mode. The integration time for each pointing was 10 min. We discovered a new pulsar, PSR J1845–0306, which has a spin period of 983.6 ms and a dispersion measure of 444.6 ± 2.0 cm−3⋅pc, in observations of SNR G29.6+0.1. To judge the association between the pulsar and the SNR, further verification is needed. We also re-detected some known pulsars in the data from SNRs G29.6+0.1 and G29.7–0.3. No pulsars were detected in the observations of the other three SNRs.
Electrostatically actuated all metal MEMS Pirani gauge with tunable dynamic range
Authors: Garg Manu , Arya Dhairya Singh , Kumar Sushil , Joshi Khanjan , Yousuf Mujeeb , Chiu Yi , Singh Pushpapraj
Published: January 2024

An electrostatically actuated all-metal microelectromechanical systems (MEMS) Pirani gauge with a tunable dynamic range is proposed. Contrary to the conventional fixed gap Pirani gauges, an electrostatic mechanism is employed to tune the gaseous conduction gap. Due to the electrostatic force between the heating element and heat sink, this tuning results in shifting the transition pressure to a higher pressure. As a result, the operating range of the Pirani gauge can be tuned depending on the magnitude of the actuation voltage. Theoretical estimation of the transition pressure corresponding to different gaseous conduction gaps is also presented. Depending on the available margin of gap tuning, the electromechanical and electrothermal analyses are carried out in COMSOL Multiphysics. The analytical approach is validated by experimentally characterizing the fabricated device. The experimentally tested device with the proposed actuation mechanism shows an 11.2 dB increase in dynamic range in comparison to the conventional design. In a complementary metal-oxide-semiconductor (CMOS)-compatible fabrication process flow, the proposed gauge can be used to monitor vacuum from 40 Pa to 5 × 105 Pa with the electrostatic actuation.
Effects of tunable circuit parameters on pulsed discharge and input-output characteristics of a XeCl excimer laser
Authors: Chen Jiayi , Zhao Zhihang , Liu Zhigang , Fu Yangyang
Published: January 2024

High-pressure, pulsed discharge-pumped XeCl excimer lasers are operating in the ultraviolet range at a wavelength of 308 nm. In this paper, a one-dimensional fluid model coupled to a magnetic pulse compression (MPC) excitation circuit and a laser gain model is established for describing the discharge and laser output characteristics of XeCl excimer lasers. The effects of the peaking capacitor

C

p

(the terminal of the MPC circuit) on the discharge properties and input-output characteristics are explored. The results reveal that

C

p

plays a key role in suppressing discharge pulse oscillation, which in turn influences the peak value and duration of the laser pulse. By optimizing the capacitance, a maximum excimer formation efficiency of 6.6% and a maximum laser output efficiency of 5% (output energy of 1.26 J) are obtained when

C

p

=
1.12
 

C

s

, where

C

s

is the storage capacitor in the MPC circuit.
Ultrashort channel MoSe2 transistors with selenium atoms replaced at the interface: first-principles quantum-transport study
Authors: Chung Chih-Hung , Chen Ting-Yu , Lin Chiung-Yuan , Chien Huang-Wei
Published: January 2024

Realizing n- and p-type transition metal dichalcogenide (TMD)-based field-effect transistors for nanoscale complementary metal oxide semiconductor (CMOS) applications remains challenging owing to undesirable contact resistance. Quantumtransport calculations were performed by replacing single-sided Se atoms of TMD near the interface with As or Br atoms to further improve the contact resistance. Here, partial selenium replacement produced a novel interface with a segment of metamaterial MoSeX (Pt/MoSeX/MoSe2; X = As, Br). Such stable metamaterials exhibit semi-metallicity, and the contact resistance can be thus lowered. Our findings provide insights into the potential of MoSe2-based nano-CMOS logic devices.
Characteristics of tunable aluminum-doped Ga2O3 thin films and photodetectors
Authors: Ding Si-Tong , Chen Yu-Chang , Yu Qiu-Jun , Zeng Guang , Shi Cai-Yu , Shen Lei , Zhao Xue-Feng , Lu Hong-Liang
Published: January 2024

Aluminum-doped Ga2O3 (AGO) thin films were prepared by plasma-enhanced atomic layer deposition (PE-ALD). The growth mechanism, surface morphology, chemical composition, and optical properties of AGO films were systematically investigated. The bandgap of AGO films can be theoretically set between 4.65 and 6.8 eV. Based on typical AGO films, metal–semiconductor–metal photodetectors (PDs) were created, and their photoelectric response was examined. The preliminary results show that PE-ALD grown AGO films have high quality and tunable bandgap, and AGO PDs possess superior characterizations to undoped films. The AGO realized using PE-ALD is expected to be an important route for the development of a new generation of gallium oxide-based photodetectors into the deep-ultraviolet.
Facile preparation of MoO3@Mo2CT
x
nanocomposite with high lithium storage performance by in situ oxidation
Authors: Guo Yitong , Xia Qixun , Chang Yukai , Wang Libo , Zhou Aiguo
Published: January 2024

In this work, a new MoO3@Mo2CT
x
nanocomposite was prepared from two–dimensional (2D) Mo2CT
x
MXene by in situ oxidization in air, which exhibited wonderful lithium-storage performance as anodes of lithium–ion batteries (LIBs). The precursor Mo2CT
x
was synthesized from Mo2Ga2C by selective etching of NH4F at 180 °C for 24 h. Thereafter, the Mo2CT
x
was oxidized in air at 450 °C for 30 min to obtain MoO3@Mo2CT
x
nanocomposite. In the composite, in situ generated MoO3 nanocrystals pillar the layer structure of Mo2CT
x
MXene, which increases the interlayer space of Mo2CT
x
for Li storage and enhances the structure stability of the composite. Mo2CT
x
2D sheets provide a conductive substrate for MoO3 nanocrystals to enhance the Li+ accessibility. As anodes of LIBs, the final discharge specific capacity of the MoO3@Mo2CT
x
composite was 511.1 mAh g–1 at a current density of 500 mA g–1 after 100 cycles, which is about 36.7 times that of pure Mo2CT
x
MXene (13.9 mAh g–1) and 3.2 times that of pure MoO3 (159.9 mAh g–1). In the composites, both Mo2CT
x
and MoO3 provide high lithium storage capacity and can enhance the performance of each other. Moreover, this composite can be made by a facile method of in situ oxidation. Therefore, the MoO3@Mo2CT
x
MXene nanocomposite is a promising anode of LIB with high performance.
Cusps in heavy billiards
Authors: Hasselblatt Boris , Yeun Kim Ki , Levi Mark
Published: January 2024

We consider billiards with cusps and with gravity pulling the particle into the cusp. We discover an adiabatic invariant in this context; it turns out that the invariant is in form almost identical to the Clairaut integral (angular momentum) for surfaces of revolution. We also approximate the bouncing motion of a particle near a cusp by smooth motion governed by a differential equation—which turns out to be identical to the differential equation governing geodesic motion on a surface of revolution. We also show that even in the presence of gravity pulling into a cusp of a billiard table, only the direct-hit orbit reaches the tip of the cusp. Finally, we provide an estimate of the maximal depth to which a particle penetrates the cusp before being ejected from it.
Classification and stability of positive solutions to the NLS equation on the
T
-metric graph
Authors: Agostinho Francisco , Correia Simão , Tavares Hugo
Published: January 2024

Given λ > 0 and p > 2, we present a complete classification of the positive H
1-solutions of the equation

−

u

′
′

+
λ
u
=

|

u

|

p
−
2

u

on the

T

-metric graph (consisting of two unbounded edges and a terminal edge of length

ℓ
>
0

, all joined together at a single vertex). This study implies, in particular, the uniqueness of action ground states. Moreover, for

p
∼

6
−

, the notions of action and energy ground states do not coincide and energy ground states are not unique. In the L
2-supercritical case p > 6, we prove that, for

λ
∼

0
+

and

λ
∼
+
∞

, action ground states are orbitally unstable for the flow generated by the associated time-dependent NLS equation

i

∂
t

u
+

∂

x
x

2

u
+

|

u

|

p
−
2

u
=
0

. Finally, we provide numerical evidence of the uniqueness of energy ground states for

p
∼

2
+

and of the existence of both stable and unstable action ground states for

p
∼
6

.
Investigating the impact of smoking habits through photoplethysmography analysis
Authors: Qananwah Qasem , Khader Ateka , Al-Hashem Munder , Mumani Ahmad , Dagamseh Ahmad
Published: January 2024

Smoking is widely recognized as a significant risk factor in the progression of arterial stiffness and cardiovascular diseases. Valuable information related to cardiac arrhythmias and heart function can be obtained by analyzing biosignals such as the electrocardiogram (ECG) and the photoplethysmogram (PPG). The PPG signal is a non-invasive optical technique that can be used to evaluate the changes in blood volume, and thus it can be linked to the health of the vascular system. Objective. In this study, the impact of three smoking habits—cigarettes, shisha, and electronic cigarettes (e-cigarettes)—on the features of the PPG signal were investigated. Approach. The PPG signals are measured for 45 healthy smokers before, during, and after the smoking session and then processed to extract the morphological features. Quantitative statistical techniques were used to analyze the PPG features and provide the most significant features of the three smoking habits. The impact of smoking is observed through significant changes in the features of the PPG signal, indicating blood volume instability. Main results. The results revealed that the three smoking habits influence the characteristics of the PPG signal significantly, which presentseven after 15 min of smoking. Among them, shisha has the greatest impact on PPG features, particularly on heart rate, systolic time, augmentation index, and peak pulse interval change. In contrast, e-cigarettes have the least effect on PPG features. Interestingly, smoking electronic cigarettes, which many participants use as a substitute for traditional cigarettes when attempting to quit smoking, has nearly a comparable effect to regular smoking. Significance. The findings suggest that individuals who smoke shisha are more likely to develop cardiovascular diseases at an earlier age compared to those who have other smoking habits. Understanding the variations in the PPG signal caused by smoking can aid in the early detection of cardiovascular disorders and provide insight into cardiac conditions. This ultimately contributes to the prevention of the development of cardiovascular diseases and the development of a health screening system.
Generation of meter-scale hydrogen plasmas and efficient, pump-depletion-limited wakefield excitation using 10 GeV electron bunches
Authors: Zhang C , Storey D , San Miguel Claveria P , Nie Z , Marsh K A , Hogan M , Mori W B , Adli E , An W , Ariniello R , Cao G J , Clarke C , Corde S , Dalichaouch T , Doss C E , Emma C , Ekerfelt H , Gerstmayr E , Gessner S , Hansel C , Knetsch A , Lee V , Li F , Litos M , O’Shea B , White G , Yocky G , Zakharova V , Joshi C
Published: January 2024

High repetition rates and efficient energy transfer to the accelerating beam are important for a future linear collider based on the beam-driven plasma wakefield acceleration scheme (PWFA-LC). This paper reports the first results from the Plasma Wakefield Acceleration Collaboration (E300) that are beginning to address both of these issues using the recently commissioned FACET-II facility at SLAC national accelerator laboratory. We have generated meter-scale hydrogen plasmas using time-structured 10 GeV electron bunches from FACET-II, which hold the promise of dramatically increasing the repetition rate of PWFA by rapidly replenishing the gas between each shot compared to the hitherto used lithium plasmas that operate at 1–10 Hz. Furthermore, we have excited wakes in such plasmas that are suitable for high gradient particle acceleration with high drive-bunch to wake energy transfer efficiency- a first step in achieving a high overall energy transfer efficiency. We have done this by using time-structured electron drive bunches that typically have one or more ultra-high current (

>

30 kA) femtosecond spike(s) superimposed on a longer (∼0.4 ps) lower current (

<

10 kA) bunch structure. The first spike effectively field-ionizes the gas and produces a meter-scale (30–160 cm) plasma, whereas the subsequent beam charge creates a wake. The length and amplitude of the wake depends on the longitudinal current profile of the bunch and plasma density. We find that the onset of pump depletion, when some of the drive beam electrons are nearly fully depleted of their energy, occurs for hydrogen pressure

⩾

1.5 Torr. We also show that some electrons in the rear of the bunch can gain several GeV energies from the wake. These results are reproduced by particle-in-cell simulations using the QPAD code. At a pressure of ∼2 Torr, simulation results and experimental data show that the beam transfers about 60% of its energy to the wake.
Low-resistive gate module for RF GaN-HFETs by electroplating
Authors: Yazdani H , Thies A , Stützle P , Bengtsson O , Hilt O , Heinrich W , Würfl J
Published: January 2024

This paper presents a novel approach for reducing the gate resistance (R
g) of K and Ka-band GaN HFETs with 150 nm gate length through a new gate metallization technique. The method involves increasing the gate cross-section via galvanic metallization using FBH’s Ir-sputter gate technology, which allows an increase in gate metal thickness from the current 0.4 μm to approximately 1.0 μm for the transistors under investigation. This optimization leads to a substantial 50% reduction in gate series resistance, resulting in significant improvements in the RF performance. Specifically, the devices achieve 20% higher output power density and 10% better power-added efficiency at 20 GHz and V
ds = 20 V. The decreased gate resistance enables new degrees of freedom in design, such as longer gate fingers and/or shorter gate lengths, for more efficient power cells operating in this frequency range.
On the coupling of magnetic moments to superconducting quantum interference devices
Authors: Linek J , Wyszynski M , Müller B , Korinski D , Milošević M V , Kleiner R , Koelle D
Published: January 2024

We investigate the coupling factor φ

µ
that quantifies the magnetic flux Φ per magnetic moment µ of a point-like magnetic dipole that couples to a superconducting quantum interference device (SQUID). Representing the dipole by a tiny current-carrying (Amperian) loop, the reciprocity of mutual inductances of SQUID and Amperian loop provides an elegant way of calculating

ϕ
μ

(
r
,

e
ˆ

μ

)

vs. position

r

and orientation

e
ˆ

μ

of the dipole anywhere in space from the magnetic field

B
J

(
r
)

produced by a supercurrent circulating in the SQUID loop. We use numerical simulations based on London and Ginzburg–Landau theory to calculate φ

µ
from the supercurrent density distributions in various superconducting loop geometries. We treat the far-field regime (

r
≳
a
=

inner size of the SQUID loop) with the dipole placed on (oriented along) the symmetry axis of circular or square shaped loops. We compare expressions for φ

µ
from simple filamentary loop models with simulation results for loops with finite width w (outer size A > a), thickness d and London penetration depth λ
L and show that for thin (

d
≪
a

) and narrow (w < a) loops the introduction of an effective loop size

a

eff

in the filamentary loop-model expressions results in good agreement with simulations. For a dipole placed right in the center of the loop, simulations provide an expression

ϕ
μ

(
a
,
A
,
d
,

λ

L

)

that covers a wide parameter range. In the near-field regime (dipole centered at small distance z above one SQUID arm) only coupling to a single strip representing the SQUID arm has to be considered. For this case, we compare simulations with an analytical expression derived for a homogeneous current density distribution, which yields excellent agreement for

λ

L

>
w
,
d

. Moreover, we analyze the improvement of φ

µ
provided by the introduction of a narrow constriction in the SQUID arm below the magnetic dipole.
Ordering dynamics and aging in the symmetrical threshold model
Authors: Abella David , González-Avella Juan Carlos , San Miguel Maxi , Ramasco José J
Published: January 2024

The so-called Granovetter–Watts model was introduced to capture a situation in which the adoption of new ideas or technologies requires a certain redundancy in the social environment of each agent to take effect. This model has become a paradigm for complex contagion. Here we investigate a symmetric version of the model: agents may be in two states that can spread equally through the system via complex contagion. We find three possible phases: a mixed one (dynamically active disordered state), an ordered one, and a heterogeneous frozen phase. These phases exist for several configurations of the contact network. Then, we consider the effect of introducing aging as a non-Markovian mechanism in the model, where agents become increasingly resistant to change their state the longer they remain in it. We show that when aging is present, the mixed phase is replaced, for sparse networks, by a new phase with different dynamical properties. This new phase is characterized by an initial disordering stage followed by a slow ordering process toward a fully ordered absorbing state. In the ordered phase, aging modifies the dynamical properties. For random contact networks, we develop a theoretical description based on an approximate master equation that describes with good accuracy the results of numerical simulations for the model with and without aging.
Information cascade prediction of complex networks based on physics-informed graph convolutional network
Authors: Yu Dingguo , Zhou Yijie , Zhang Suiyu , Li Wenbing , Small Michael , Shang Ke-ke
Published: January 2024

Cascade prediction aims to estimate the popularity of information diffusion in complex networks, which is beneficial to many applications from identifying viral marketing to fake news propagation in social media, estimating the scientific impact (citations) of a new publication, and so on. How to effectively predict cascade growth size has become a significant problem. Most previous methods based on deep learning have achieved remarkable results, while concentrating on mining structural and temporal features from diffusion networks and propagation paths. Whereas, the ignorance of spread dynamic information restricts the improvement of prediction performance. In this paper, we propose a novel framework called Physics-informed graph convolutional network (PiGCN) for cascade prediction, which combines explicit features (structural and temporal features) and propagation dynamic status in learning diffusion ability of cascades. Specifically, PiGCN is an end-to-end predictor, firstly splitting a given cascade into sub-cascade graph sequence and learning local structures of each sub-cascade via graph convolutional network , then adopting multi-layer perceptron to predict the cascade growth size. Moreover, our dynamic neural network, combining PDE-like equations and a deep learning method, is designed to extract potential dynamics of cascade diffusion, which captures dynamic evolution rate both on structural and temporal changes. To evaluate the performance of our proposed PiGCN model, we have conducted extensive experiment on two well-known large-scale datasets from Sina Weibo and ArXIv subject listing HEP-PH to verify the effectiveness of our model. The results of our proposed model outperform the mainstream model, and show that dynamic features have great significance for cascade size prediction.
Design and performance analysis of Si-SiGe heterostructure based double gate feedback FET
Authors: Das Subir , Katta Sai Shirov , Raj Pushp , Singh Jawar , Tiwari Pramod Kumar
Published: January 2024

The design and performance analysis of a Si-SiGe heterostructure-based double gate feedback field-effect transistor (HDG FBFET) are presented in this paper. The proposed HDG FBFET is capable of providing high on current (3 × 10−4 A/μm) with a large I

ON
/I

OFF
ratio (3 × 1011) and is scalable up to 20 nm channel length. Its exceptionally steep switching characteristics (SS < 1 mV/decade) and ability to switch ON/OFF at lower gate voltage due to the use of smaller band-gap material (Si1−x
Ge
x
) in channel-2 and drain regions make it suitable for use in low power applications. A significant hysteresis window of 4.99 V is also achieved by the device, which can be extremely helpful for memory applications. Moreover, a comprehensive investigation of the nature of hysteresis in relation to the different device parameters has also been carried out. The designing of the device structure and all of the electrical performance characterization have been done using the Sentaurus TCAD tool.
Hartree-fock roothaan calculations using optimized huzinaga orbitals on small molecules
Authors: Jaelani Achmad , Riyanto Fiqri A , Prayitno Teguh B , Sarwono Yanoar P
Published: January 2024

We present the ground-state solution of some small molecules using the Hartree–Fock Roothaan method with the optimized Huzinaga basis set. Unlike the previously used least-square methods, the contraction coefficients and exponents of Huzinaga-parameterized primitive Gaussian functions for minimal basis sets are energy-optimized at the atomic level for each molecule. Consequently, as an alternative to and in comparison with standard parameterization, the optimized orbitals significantly improve the total energy and the equilibrium bond length with substantial enhancement shown for heavier nuclei. Despite similar computational cost, the application of our scheme leads to much improved minimal-basis-set Hartree–Fock calculations with less required parameters to match the large basis set calculations. Furthermore, the localization of the electrons near the nuclei which is missing with the standard parameterization is observed with the current scheme.
Derivation of Rytov variance for jet engine-induced turbulence
Authors: Oktay Semih , Bayraktar Mert , Tabaru Timuçin Emre , Chatzinotas Symeon
Published: January 2024

In this study, we analytically derived the Rytov variance and scintillation index value of turbulence caused by jet engines. In addition, we analyzed the variation characteristics of the Rytov variance and scintillation index values numerically depending on the variations in turbulence strength, experimental data, and wavelength. We observe that Rytov variance reaches up to high values due to the strong turbulence resulting from high refractive index fluctuations. This result brings high-intensity fluctuations regardless of the anisotropy of the turbulence. Rytov variance is directly proportional to turbulence strength. We present scintillation index curves considering the aperture averaged case. We plot our results considering the variations in the operating wavelength, turbulence strength, and the scaling parameter. According to our results, we think that it will be useful for a system such as directed infrared countermeasure (DIRCM), which is highly sensitive and should be exposed to minimum turbulence in the field of use. Since DIRCMs transmit codes to paralyze the missile’s seeker, intensity fluctuations play a vital role during this transmission. It could reduce the performance of these systems when intensity fluctuations are high.
Crystal structure, phase transitions, dielectric and conduction mechanisms of the new long chain organic-inorganic hybrid [(CH2)8(NH3)2]CoCl4
Authors: Mostafa Mohga F , Tammam Ahmed K
Published: January 2024

Two dimensional long chain organic inorganic hybrid [NH3(CH2)8NH3]CoCl4, (2C8CoCl) crystallizes in triclinic system, (P1/P

1

̅

), lattice parameters: a = 8.368 Ǻ, b = 12.888 Ǻ, c = 15.045 Ǻ, α = 97.56°, β = 86.82°, γ = 89.82°, Z = 4, d = 1.44 gm cm−3 and V = 1597.3 Ǻ3. Calculated lattice potential energy (ΔUpot) and change of enthalpy (ΔH) are ΔUpot = 1835.01 (kJ mol−1) and ΔH = 425.92 (kJ mol−1) respectively. Thermal study using differential thermal analysis (DTA) and thermogravimetric analysis (TGA) confirm different phase transitions, in the temperature range (300 < T(K) < 500) with onset temperatures at T1 = 401 ± 1 K, T2 = 358.3 K and T3 = 328.9 K, such transitions are reflected in impedance spectroscopy. The transition at T3 corresponds to chain melting. Dielectric constant and ac-conductivity are studied in the temperature range (300 < T (K) < 420) and frequency range (0.11 < f(kHz) < 65). Three different thermally activated conduction regions were observed corresponding to phases I (404–414) K; (ΔEo~ 0.83 eV), II (360–400) K; (ΔEo~ 1.19 eV) and III (T < 348 K); ΔEo = (0.03 eV– 0.006 eV). Equivalent circuit derived from impedance analysis, is composed of combination of resistor and two series of parallel (R//CPE) circuits. Super-linear power law dominates for ac- conduction in the measured temperature ranges. Conduction mechanism is analyzed on the basis of different conduction models which varies as the phases change. Quantum mechanical tunneling prevails at low temperatures with s value ~0.77 while correlated barrier hopping dominates in the range (363 < T (K) < 400) with barrier height WM = 0.34 eV. Comparison to previously studied long chain hybrids [NH3(CH2)nNH3]CoCl4, n = 6 and 7 is discussed. A linear decrease in lattice potential energy and enthalpy values is observed as chain length increases. The room temperature conductivity reveals that σ
ac(2C7CoCl) > σ
ac(2C6CoCl) >σ
ac(2C8CoCl), which is discussed in light of structural characteristics.
Spin reorientation, spin switching, and magnetic compensation in Er1−xSmxFeO3 single crystals
Authors: Bairwa Dhanpal , Elizabeth Suja
Published: January 2024

We investigated spin reorientation, magnetic compensation and spin switching transitions in a series of high-quality single crystals of Er1−xSmxFeO3 (x = 0, 0.2, 0.4, 0.6, 0.8) prepared using the optical floating zone method. Structural and other preliminary characterizations confirmed the quality and phase purity of the crystals. Rietveld refinement of powder XRD data indicates that lattice parameters a and c increase linearly with increasing Sm concentration, whereas b remained constant. Field-cooled cooling (FCC) measurements revealed a temperature-induced spin reorientation transition (SRT) from Γ4 (Gx, Ay, Fz) to Γ2 (Fx, Cy, Gz) for all the samples. SRT temperature increased with Sm concentration and spread widely above and below room temperature. Moreover, magnetic compensation is common to all the compositions but decreases as Sm doping increases. We also observe type-I spin switching in samples with x = 0, 0.2, and 0.4 at an applied field of 60 Oe under FCC protocol, with a reduction in spin switching temperature as Sm content increased. For Sm-rich samples (x = 0.6, 0.8), spin switching was absent at 60 Oe.
Hollow cathode effect in radio frequency hollow electrode discharge in argon
Authors: He 贺 Liu-Liang 柳良 , He 何 Feng 锋 , Ouyang 欧 Ji-Ting 阳吉庭
Published: January 2024

Radio frequency capacitively coupled plasma source (RF-CCP) with a hollow electrode can increase the electron density through the hollow cathode effect (HCE), which offers a method to modify the spatial profiles of the plasma density. In this work, the variations of the HCE in one RF period are investigated by using a two-dimensional particle-in-cell/Monte-Carlo collision (PIC/MCC) model. The results show that the sheath electric field, the sheath potential drop, the sheath thickness, the radial plasma bulk width, the electron energy distribution function (EEDF), and the average electron energy in the cavity vary in one RF period. During the hollow electrode sheath’s expansion phase, the secondary electron heating and sheath oscillation heating in the cavity are gradually enhanced, and the frequency of the electron pendular motion in the cavity gradually increases, hence the HCE is gradually enhanced. However, during the hollow electrode sheath’s collapse phase, the secondary electron heating is gradually attenuated. In addition, when interacting with the gradually collapsed hollow electrode sheaths, high-energy plasma bulk electrons in the cavity will lose some energy. Furthermore, the frequency of the electron pendular motion in the cavity gradually decreases. Therefore, during the hollow electrode sheath’s collapse phase, the HCE is gradually attenuated.
Microwave electrometry with Rydberg atoms in a vapor cell using microwave amplitude modulation
Authors: Hao 郝 Jian-Hai 建海 , Jia 贾 Feng-Dong 凤东 , Cui 崔 Yue 越 , Wang 王 Yu-Han 昱寒 , Zhou 周 Fei 飞 , Liu 刘 Xiu-Bin 修彬 , Zhang 张 Jian 剑 , Xie 谢 Feng 锋 , Bai 白 Jin-Hai 金海 , You 尤 Jian-Qi 建琦 , Wang 王 Yu 宇 , Zhong 钟 Zhi-Ping 志萍
Published: January 2024

We have theoretically and experimentally studied the dispersive signal of the Rydberg atomic electromagnetically-induced transparency (EIT) Autler–Townes (AT) splitting spectra obtained using amplitude modulation of the microwave (MW) electric field. In addition to the two zero-crossing points interval Δf
zeros, the dispersion signal has two positive maxima with an interval defined as the shoulder interval Δf
sho, which is theoretically expected to be used to measure a much weaker MW electric field. The relationship of the MW field strength E
MW and Δf
sho is experimentally studied at the MW frequencies of 31.6 GHz and 9.2 GHz respectively. The results show that Δf
sho can be used to characterize the much weaker E
MW than that of Δf
zeros and the traditional EIT–AT splitting interval Δf
m; the minimum E
MW measured by Δf
sho is about 30 times smaller than that by Δf
m. As an example, the minimum E
MW at 9.2 GHz that can be characterized by Δf
sho is 0.056 mV/cm, which is the minimum value characterized by the frequency interval using a vapor cell without adding any auxiliary fields. The proposed method can improve the weak limit and sensitivity of E
MW measured by the spectral frequency interval, which is important in the direct measurement of weak E
MW.
Electromagnetic pulses produced by a picosecond laser interacting with solid targets
Authors: Niu 牛 Ai-Hui 爱慧 , Kang 康 Ning 宁 , Xu 许 Guo-Xiao 国潇 , Xie 谢 Jia-Jie 佳节 , Teng 滕 Jian 建 , Liu 刘 Hui-Ya 会亚 , Sun 孙 Ming-Ying 明营 , Li 李 Ting-Shuai 廷帅
Published: January 2024

A high-power laser ablating solid targets induces giant electromagnetic pulses (EMPs), which are intimately pertinent to laser parameters, such as energy and pulse width. In this study, we reveal the features of EMPs generated from a picosecond (ps) laser irradiating solid targets at the SG-II picosecond petawatt (PSPW) laser facility. The laser energy and pulse, as well as target material and thickness, show determinative effects on the EMPs’ amplitude. More intense EMPs are detected behind targets compared to those at the other three positions, and the EMP amplitude decreases from 90.09 kV/m to 17.8 kV/m with the gold target thickness increasing from 10 μm to 20 μm, which is suppressed when the laser pulse width is enlarged. The results are expected to provide more insight into EMPs produced by ps lasers coupling with targets and lay the foundation for an effective EMP shielding design in high-power laser infrastructures.
EEG-based hierarchical classification of level of demand and modality of auditory and visual sensory processing
Authors: Massaeli Faghihe , Power Sarah D
Published: January 2024

Objective. To date, most research on electroencephalography (EEG)-based mental workload detection for passive brain-computer interface (pBCI) applications has focused on identifying the overall level of cognitive resources required, such as whether the workload is high or low. We propose, however, that being able to determine the specific type of cognitive resources being used, such as visual or auditory, would also be useful. This would enable the pBCI to take more appropriate action to reduce the overall level of cognitive demand on the user. For example, if a high level of workload was detected and it is determined that the user is primarily engaged in visual information processing, then the pBCI could cause some information to be presented aurally instead. In our previous work we showed that EEG could be used to differentiate visual from auditory processing tasks when the level of processing is high, but the two modalities could not be distinguished when the level of cognitive processing demand was very low. The current study aims to build on this work and move toward the overall objective of developing a pBCI that is capable of predicting both the level and the type of cognitive resources being used. Approach. Fifteen individuals undertook carefully designed visual and auditory tasks while their EEG data was being recorded. In this study, we incorporated a more diverse range of sensory processing conditions including not only single-modality conditions (i.e. those requiring one of either visual or auditory processing) as in our previous study, but also dual-modality conditions (i.e. those requiring both visual and auditory processing) and no-task/baseline conditions (i.e. when the individual is not engaged in either visual or auditory processing). Main results. Using regularized linear discriminant analysis within a hierarchical classification algorithm, the overall cognitive demand was predicted with an accuracy of more than 86%, while the presence or absence of visual and auditory sensory processing were each predicted with an accuracy of approximately 70%. Significance. The findings support the feasibility of establishing a pBCI that can determine both the level and type of attentional resources required by the user at any given moment. This pBCI could assist in enhancing safety in hazardous jobs by triggering the most effective and efficient adaptation strategies when high workload conditions are detected.
Modified motor unit properties in residual muscle following transtibial amputation
Authors: Rubin Noah , Hinson Robert , Saul Katherine , Filer William , Hu Xiaogang , Huang He (Helen)
Published: January 2024

Objective. Neural signals in residual muscles of amputated limbs are frequently decoded to control powered prostheses. Yet myoelectric controllers assume muscle activities of residual muscles are similar to that of intact muscles. This study sought to understand potential changes to motor unit (MU) properties after limb amputation. Approach. Six people with unilateral transtibial amputation were recruited. Surface electromyogram (EMG) of residual and intact tibialis anterior (TA) and gastrocnemius (GA) muscles were recorded while subjects traced profiles targeting up to 20% and 35% of maximum activation for each muscle (isometric for intact limbs). EMG was decomposed into groups of MU spike trains. MU recruitment thresholds, action potential amplitudes (MU size), and firing rates were correlated to model Henneman’s size principle, the onion-skin phenomenon, and rate-size associations. Organization (correlation) and modulation (rates of change) of relations were compared between intact and residual muscles. Main results. The residual TA exhibited significantly lower correlation and flatter slopes in the size principle and onion-skin, and each outcome covaried between the MU relations. The residual GA was unaffected for most subjects. Subjects trained prior with myoelectric prostheses had minimally affected slopes in the TA. Rate-size association correlations were preserved, but both residual muscles exhibited flatter decay rates. Significance. We showed peripheral neuromuscular damage also leads to spinal-level functional reorganizations. Our findings suggest models of MU recruitment and discharge patterns for residual muscle EMG generation need reparameterization to account for disturbances observed. In the future, tracking MU pool adaptations may also provide a biomarker of neuromuscular control to aid training with myoelectric prostheses.
Bursting core-localized ellipticity-induced Alfvén eigenmodes driven by energetic electrons during EAST ohmic discharges
Authors: Su P. , Lan H. , Zhou C. , Bao J. , Liu A. , Zhu X. , Wu M. , Luo C. , Han J. , Wang J. , Liu H. , Zhang T. , Zhou R. , Lin S. , Zhao H. , Sun Y. , Qiu Z. , Chu N. , Tang T. , Tan Y. , Zeng L. , Gao Z.
Published: January 2024

A series of high-frequency (

400
∼
1000

 kHz

) bursting core-localized Alfvén instabilities have been observed during ohmic discharges in EAST tokamak. The instability trigger favours the discharge conditions of low toroidal magnetic field and low electron density. The toroidal mode numbers are mainly

n
=
2
∼
3

and they propagate in the ion diamagnetic drift (co-current) direction. These modes are radially localized in the range of

ρ

tor

=
0.2
∼
0.35

based on Doppler BackScatter measurement. They are identified as ellipticity-induced Alfvén eigenmodes (EAEs) occurring at

q
=
1

rational surfaces by magnetohydrodynamics simulations using the realistic geometry and plasma profiles. The EAEs show regular bursts with ∼10 ms duration along with the mode frequency chirping downwards and upwards rapidly. It is also found that sawtooth events can interrupt the growth and evolution of the EAEs, causing the modes to disappear immediately. Passing energetic electrons (EEs) that move much faster than Alfvén velocity are responsible for the destabilization of these EAEs, which attribute to the fact that the large poloidal and toroidal frequencies mostly cancel each other and satisfy the EAE resonance condition with primary energy exchange. These novel experimental results of the wave-particle interaction between EAEs and EEs are helpful for extrapolating alpha particle physics that are characterized by small orbit width with respect to machine size in future fusion reactors.
Pattern recognition and signal parameters extraction using machine learning methods
Authors: Buchakchiev Valentin , Dimitrova Kalina , Georgiev Georgi , Georgieva Gergana , Kozhuharov Venelin
Published: January 2024

Machine learning methods can be used for signal processing in different cases of physics research. A convolutional neural network was developed for the task of pulse counting in particle detectors for high energy physics. For the extraction of signal parameters was used a network with convolutional autoencoder architecture and a subsequent result reconstruction algorithm was developed and applied. A convolutional neural network was also developed for seismic studies with the task of identifying different events in seismograms. All of the algorithms with their architecture, input and output are presented and discussed.