bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aging of epoxy cast insulation with different voltages and environmental stresses
Authors: Shang Xingyu , Pang Lei , Tang Wanlin , Bu Qinhao , Zhang Qiaogen 
Published: September 2024

Abstract
Power electronic conversion systems introduce different types of voltage stresses on high-voltage epoxy cast insulation in medium-frequency transformers (MFTs), which challenges the reliability of MFTs. The endurance of epoxy insulation at different voltages (AC, DC and pulse) and environmental (thermal and humidity) stresses was studied using encapsulated electrodes in the absence of partial discharge. To assess aging processes and select aging state indicators, various tests including AC breakdown strength (BDE), broadband dielectric spectroscopy, small-angle x-ray scattering (SAXS), Fourier-transform infrared spectroscopy and differential scanning calorimetry (DSC) were first conducted on aged flat samples. The increase of mesoscopic free volume from the SAXS result and local densification (physical aging) of epoxy network from the DSC result were both found. BDE is proved to be sensitive to various aging conditions and thus determined as a test method for encapsulated samples. It is found that the physical aging effect under thermal stress at early aging stages can cause a reversible increase in BDE compared to non-aged samples. This effect can be erased by coupled medium-low electrical stress during aging. In contrast, a sufficiently high electric field will deepen the physical aging extent. Occasional sample failures were observed simultaneously within this process. According to the SAXS and DSC results on flat samples, the failure of encapsulated samples is possibly attributed to the chain fracture around increased mesoscopic free volume during electron bombardment and microcracks generated by interfacial stress release during physical aging. At longer aging periods, the volumetric absorption and diffusion of chemical reactants (oxygen and water) in epoxy networks at high temperatures determines the eventual decrease in BDE, which can be accelerated by the electric field. Ages with different voltage types were gauged by the reduction of BDE compared to pure environmental stress. Bipolar pulses bring heavier aging effects than ACs at the same RMS value. However, the DC component has opposite effects on the BDE with and without thermal stress.
On the charge transport models in high intrinsic defect doped transparent and conducting p-type Cu–Cr–O delafossite thin films
Authors: Crepelliere Jonathan , Moreira Marco , Lunca-Popa Petru , Leturcq Renaud , Lenoble Damien 
Published: September 2024

Abstract
In contemporary optoelectronic devices, the transparent conductive oxides commonly demonstrate n-type conduction characteristics, with indium-doped tin oxide emerging as a prominent example. However, in applications involving fully invisible electronics that necessitate p-type conductive oxides, there exists a demand for a quintessential material possessing properties akin to its n-type counterpart. CuCrO2, a delafossite semiconductor based on copper, presently represents a notable compromise between optical and electrical attributes within the realm of p-type semiconductors. Despite numerous studies focusing on this material, the charge carrier transport regime within the material remains unclear. The commonly reported hole transport mechanism in CuCrO2 is the small polaron model. However, this work evidences several contradictions when this transport mechanism is assumed. Using the same methodology as previous studies, we investigated the holes’ transport mechanism by the means of the measurement of electrical conductivity and the Seebeck coefficient at varying temperatures. Different charge transport models in high intrinsic defect doped CuCrO2 thin films are explored: small polarons, grain boundaries scattering in degenerate semiconductors, and variable range hopping with nearest neighbor hopping. The small polaron model does not provide conclusive results within the temperature range analyzed. Interestingly, no specific hole transport mechanism can be undoubtedly selected. The limitations of the models highlight the influence of peculiar defects within CuCrO2 thin films on the hole transport mechanism, particularly the adoption of well-ordered copper vacancies columns.
Physical understanding of a normally off p-GaN/AlGaN/GaN HEMT gate stack and a review of VTH measurement techniques
Authors: Murukesan Karthick , Efthymiou Loizos , Udrea Florin 
Published: September 2024

Abstract
In this report, a comprehensive review of the variations in threshold voltage (V
TH) that could arise due to different V
TH measurement techniques, V
TH measurement bias conditions and V
TH extraction techniques is made. Notably, a standard deviation of 15% is observed in threshold voltage values due to variations in measurement methodology and bias conditions. This variation is attributed to the change in the dynamic gate charge conditions across the gate stack and lateral electric field conditions across the gate and drain, which occur due to the change in measurement conditions and the bias conditions, respectively. No significant variations arise due to the V
TH extraction technique. Additionally, a simplified physical interpretation of the gate stack in normally off p-GaN gate/AlGaN/GaN on Si high electron mobility transistors is made. The formation of the two-dimensional electron gas, the charge balance within the p-GaN/AlGaN/GaN gate stack and an analytical expression for the threshold voltage are reviewed and examined. Furthermore, various trapping mechanisms within the gate stack are reviewed to comprehend the dynamic conditions potentially contributing to threshold voltage instability during nominal operation.
Ionizing radiation and skin cancer—a review of current evidence
Authors: Caramenti Luca , Breckow Joachim , Hildebrandt Guido , Drexler Hans , Volkmer Beate , Hauptmann Michael 
Published: September 2024

Abstract
Cancer of the skin represents a challenge for radiological protection, as it is very common and involves the largest organ of the human body, which is exposed to environmental stress, including ionizing radiation (IR). The most common subtypes, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), have very low mortality. Current consideration of skin cancer in radiological protection is mainly based on data from the 1990s, which indicate that BCC may be induced by IR, SCC is only weakly associated with IR, and malignant melanoma (MM) is not considered as IR-induced. In a semi-systematic review of the evidence between 1990 and 2023, we snowballed 20 index articles. We identified 33 articles with information on a potential dose-response relationship between skin cancer and IR exposure and assessed the evidence for a causal association. Exposure situations included a-bomb survivors, therapeutic and occupational exposure (airlines, nuclear and medical facilities) and residents exposed to radon or other radiation sources. There is currently no epidemiological evidence that MM or SCC are caused by IR. The only skin cancer type with evidence for a causal relationship is BCC, and evidence is limited to exposures above about 0.5 Gy with a wide range of risk levels per dose. Thus, IR-inducible skin cancer refers to BBC only and only at levels of exposure beyond those experienced by the vast majority of people exposed today.
Simple, innovative and attractive approach for geometrical optics, chromatic aberration and colour combination experiments
Authors: Rivera-Ortega Uriel 
Published: September 2024

Abstract
The laws of reflection and refraction and therefore the basic concepts of image formation with lenses are some topics that geometric optics deals with. Therefore, in this manuscript, laboratory practices are proposed that will cover concepts of geometric optics using both technological tools and everyday materials that allow the undergraduate or graduate student to obtain these concepts leaving the classical way in which they are usually addressed in classrooms or laboratories. Activities are also proposed that demonstrate phenomena such as chromatic aberration and the combination of red, green and blue (RGB) colours. For this purpose, electronic devices such as a Raspberry-pi (with a sense HAT module), a commercial programmable LED matrix, a hollow Christmas spheres, etc, will be used; giving a novel approach and allowing the use of new motivating technologies for both students and/or educators.
Heating characteristic of electron Bernstein wave using high-field side X-mode injection in QUEST
Authors: Murakami Takahiro , Kojima Shinichiro , Hanada Kazuaki , Idei Hiroshi , Ido Takeshi , Ikezoe Ryuya , Hasegawa Makoto , Onchi Takumi , Kono Kaori , Kuroda Kengoh , Ejiri Akira 
Published: September 2024

Abstract
A comparative investigation was conducted to assess the impact of high-field side (HFS) extraordinary (X) mode (HFS X) injection and low-field side (LFS) ordinary (O) mode (LFS O) injection of 8.2 GHz radio frequency (RF) power in the Q-shu University experimental steady-state spherical tokamak. In the case of the HFS X injection, the ratio of electron plasma frequency and RF frequency

f

pe

/

f

RF

was 1.3, indicating an overdense plasma, whereas in the LFS O injection, this ratio was 0.9. Distinctive features emerged in the electron temperature and density profiles between the two injection scenarios. In the HFS X injection, the profiles peaked between the fundamental electron cyclotron resonance (ECR) layer and the upper hybrid resonance layer. Conversely, in the LFS O injection, the peaks were situated near the 1st ECR layer. This implies effective excitation of the electron Bernstein wave (EBW) in the case of the HFS X injection, with the wave power being absorbed through the doppler-shifted ECR of the EBW. Density and temperature oscillations were observed only in the start-up phase of the HFS X injection, which may correlate with the presence of the left-hand cutoff of the X-mode. These findings will be contributed to understand the distinctive characteristics associated with plasma heating through EBW excitation in the HFS X injection.
Seismic performance improvement of a three-dimensional isolated spherical reticulated shell structure using pseudo-negative-stiffness magnetorheological dampers
Authors: Zhuang Peng , Hu Xiaoyu , Zhang Guowei 
Published: September 2024

Abstract
Three-dimensional (3D) isolation is a promising solution for providing comprehensive seismic protection to large-span spatial structures against both horizontal and vertical ground motions. This study introduces an innovative 3D isolation system for spatial reticulated shell structures using pseudo-negative-stiffness magnetorheological dampers (PNSMRDs). In the vertical direction, the PNSMRDs are connected in parallel with a prepressed spring device (PSD)-based bearing (PSDB) to form a PSDB-PNSMRD isolator that supports the reticulated shell roof. A set of semi-active control methods was established for the real-time current input to the PNSMRDs, simulating the related pseudo-negative-stiffness and energy dissipation behaviors of the damping device. A single-layer spherical reticulated shell with surrounding columns was taken as a prototype structure. The PSDB-PNSMRD isolators and concave sliding bearings were designed as a decoupled 3D isolation system for this prototype structure. For comparison, a counterpart 3D isolation system featuring passive viscous dampers was also evaluated. Seismic responses of the isolated and non-isolated structures under triaxial seismic excitations were modeled using an integrated OpenSees‒MATLAB platform. The numerical results reveal that both isolation systems are effective in mitigating structural responses, with the PSDB-PNSMRD bearings providing superior vertical isolation effects compared to passive vertical isolation bearings.
Effect of Sm2O3 on thermal, optical, mechanical, gamma and neutron shielding properties of zinc-boro-vanadate glasses
Authors: Devidas Ashwini , Sankarappa T , Malge Amarkumar , Heerasingh Mohansingh , Dyama Aravind , Pallavi Jamadar 
Published: September 2024

Abstract
The effect of Sm2O3 on thermal, optical, mechanical, gamma and neutron shielding properties of newly prepared zinc borovanadate glasses has been investigated. Density is found increased and molar volume decreased with Sm2O3 content. The glass transition temperature

(

T

g

)
,

crystallization temperature

(

T

c

)

and the peak crystallization temperature

(

T

P

)

increased with increase of rare earth oxide content. These findings demonstrated an excellent glass-forming ability and thermal stability of the glasses. The optical properties have been explored through UV–vis spectroscopy. The indirect optical band gap energy

(

E

opt

)

decreased from 2.978 to 2.679 eV, Urbach energy

(
∆
E
)

increased from 0.273 to 0.299 eV and refractive index increased from 2.403 to 2.489 with increase in Sm2O3. Elastic moduli, Poisson’s ratio, Hardness and fractal bond connectivity were computed theoretically as per Makishima Mackenzie model. It is found that these glasses have appreciable mechanical strength and rigidity. Phy-X/PSD software has been used to determine different radiation shielding characteristics for the energy range 0.015–15 MeV. The mass and linear attenuation coefficients are found higher, and half value layer, tenth value layer and mean free paths are found lower than many radiation shielding glasses quoted in the literature values. The obtained

Z

eq

values varied from 15.828–29.118 for energy range from 0.015 to 15 MeV, which are greater than those reported for several commercial glasses, concretes and rocks. Due to the Compton scattering process, exposure build up and energy absorption factor are found to be highest in the medium energy region. The fast neutron removal cross-sections of the glasses are observed to be significantly high. For the first time, thermally stable and mechanically strong zinc borovanadate glasses mixed with Sm2O3 have been thoroughly investigated for various properties and concluded that these glasses are suitable for optoelectronics and γ-shielding applications.
Three different topologies for 4-bit counters in quantum-dot cellular automata technology
Authors: Kiani Vosta Pezhman , Gholami Mohammad 
Published: September 2024

Abstract
QCA (Quantum-dot Cellular Automata) technology is an innovative technology based on quantum principles and uses quantum dots as the basic units for information transfer. This technology enables the fabrication of electronic circuits at high speed, lower power consumption and smaller size. For this reason, in this article, for the first time, three types of counters are designed in QCA technology with the least cell and the smallest area. First, Johnson ring counter with 132 cells, area of

0.16

μ
m

2

and a delay of 2 clock cycles, then synchronous counter with 192 cells and area of

0.2

μ
m

2

and finally synchronous with reset capability with 267 cells and area of ​

0.27

μ
m

2

is designed. Also, the number of cells and the occupied area of the proposed designs have improved by

25.82
%

and

35
%
,

respectively, compared to different authorities. As a result, the proposed designs are among the most optimal designs among different authorities. All the simulations were done in QCAPro and QCADesigner version 2.0.3 softwares.
Exploring thermodynamic, physical and radiative interaction properties of quinary FeNiCoCr high entropy alloys (HEAs): a multi-directional characterization study
Authors: ALMisned Ghada , Güler Ömer , Özkul İskender , Sen Baykal Duygu , Alkarrani Hessa , Kilic G , Mesbahi A , Tekin H O 
Published: September 2024

Abstract
To qualify for nuclear applications, materials must meet specific criteria, including mechanical properties, high-temperature behavior, corrosion resistance, and high-temperature oxidation resistance. High Entropy Alloys (HEAs) are particularly suitable for these applications due to their unique properties. Consequently, we conducted a theoretical and simulation-based approaches to assess some critical properties including radiation shielding properties of some quinary FeNiCoCr HEAs. In this study, we focused on quinary FeNiCoCr HEAs, whose corrosion properties have been previously examined in the literature. We investigated the thermodynamic and radiation shielding properties of HEAs with sixteen different compositions. Our methodology included evaluating thermodynamic parameters such as Mixing Entropy (∆Smix) and Mixing Enthalpy (∆Hmix), as well as structural characteristics like Valence Electron Concentration (VEC) and Atomic Size Difference (δ). This allowed us to systematically deduce the phase behavior and stability of various HEAs. Through computational modeling, we assessed the radiation shielding capabilities of these alloys, particularly their effectiveness in attenuating gamma ray and fast neutrons. The results identified FeNiCoCrW as the alloy with the lowest fast neutron removal cross-section values, highlighting its potential for nuclear applications. Its high melting point and the synergistic interplay between its elemental composition and thermodynamic properties suggest broad applicability in extreme environments. Thus, FeNiCoCrW emerges as a promising HEA with multifunctional capabilities, warranting further exploration and potential integration into advanced engineering solutions.
Modeling optical systematics for the Taurus CMB experiment
Authors: Adler Alexandre E. , Austermann Jason E. , Benton Steven J. , Duff Shannon M. , Filippini Jeffrey P. , Fraisse Aurelien A. , Gascard Thomas , Gibbs Sho M. , Gourapura Suren , Hubmayr Johannes , Gudmundsson Jon E. , Jones William C. , May Jared L. , Nagy Johanna M. , Okun Kate , Padilla Ivan , Rooney Christopher , Tartakovsky Simon , Vissers Michael R. 
Published: September 2024

Abstract
We simulate a variety of optical systematics for Taurus, a balloon-borne cosmic microwave background (CMB) polarisation experiment, to assess their impact on large-scale E-mode polarisation measurements and constraints of the optical depth to reionisation τ.
We model a one-month flight of Taurus from Wanaka, New Zealand aboard a super-pressure balloon (SPB).
We simulate night-time scans of both the CMB and dust foregrounds in the 150 GHz band, one of Taurus's four observing bands.
We consider a variety of possible systematics that may affect Taurus's observations, including non-gaussian beams, pointing reconstruction error, and half-wave plate (HWP) non-idealities.
For each of these, we evaluate the residual power in the difference between maps simulated with and without the systematic, and compare this to the expected signal level corresponding to Taurus's science goals.
Our results indicate that most of the HWP-related systematics can be mitigated to be smaller than sample variance by calibrating with Planck's TT spectrum and using an achromatic HWP model, with a preference for five layers of sapphire to ensure good systematic control.
However, additional beam characterization will be required to mitigate far-sidelobe pickup from dust on larger scales.
Quantum metrology with optimal control under an arbitrary non-Markovian bosonic environment
Authors: Zhou Likun , Yang Wen 
Published: September 2024

Abstract
Finding the optimal control is of importance to quantum metrology under a noisy environment. In this paper, we tackle the problem of finding the optimal control to enhance the performance of quantum metrology under an arbitrary non-Markovian bosonic environment. By introducing an equivalent pseudomode model, the non-Markovian dynamic evolution is reduced to a Lindblad master equation, which helps us to calculate the gradient of quantum Fisher information and perform the gradient ascent algorithm to find the optimal control. Our approach is accurate and circumvents the need for the Born–Markovian approximation. As an example, we consider the frequency estimation of a spin with pure dephasing under two types of non-Markovian environments. By maximizing the quantum Fisher information at a fixed evolution time, we obtain the optimal multi-axis control, which results in a notable enhancement in quantum metrology. The advantage of our method lies in its applicability to the arbitrary non-Markovian bosonic environment.
Effect of Mn element on shock response in CoCrFeNiMnx high entropy alloys
Authors: Wen 闻 Peng 鹏 , Du 杜 Changxing 长星 , Tao 陶 Gang 钢 , Ding 丁 Guipeng 贵鹏 
Published: September 2024

Abstract
The effect of Mn element on shock response of CoCrFeNiMn
x
high entropy alloys (HEAs) are investigated using molecular dynamics simulations. Structural analysis shows that Mn-rich CoCrFeNiMn
x
HEA has a larger average atomic volume. The elastic properties of CoCrFeNiMn
x
HEAs under various hydrostatic pressures are studied, revealing that the elastic modulus decreases with increasing of Mn content. The shock thermodynamic parameters are quantitatively analyzed. The Mn-dependent shock Hugoniot relationship of CoCrFeNiMn
x
HEAs is obtained: U
s = 1.25 + (5.21–0.011x)U
p. At relatively high shock pressure, the increase in Mn content promotes the formation of clustered BCC structures and hinders the development of dislocations. In addition, more FCC structures in Mn-rich CoCrFeNiMn
x
HEAs transform into disordered structures during spallation. Spall strength decreases with increasing Mn content. This study can provide a reference for the design and application of CoCrFeNiMn HEAs under shock loading.
Saturation of fishbone instability through zonal flows driven by energetic particle transport in tokamak plasmas
Authors: Brochard G. , Liu C. , Wei X. , Heidbrink W. , Lin Z. , Falessi M.V. , Zonca F. , Qiu Z. , Gorelenkov N. , Chrystal C. , Du X. , Bao J. , Polevoi A.R. , Schneider M. , Kim S.H. , Pinches S.D. , Liu P. , Nicolau J.H. , Lütjens H. ,   the ISEP group
Published: September 2024

Abstract
Gyrokinetic and kinetic-MHD simulations are performed for the fishbone instability in the DIII-D discharge #178631, chosen for validation of first-principles simulations to predict the energetic particle (EP) transport in an ITER pre-fusion baseline scenario. Fishbone modes are found to generate zonal flows, which dominate the fishbone saturation. The underlying mechanisms of the two-way fishbone-zonal flows nonlinear interplay are discussed in details. Numerical and analytical analyses identify the fishbone-induced EP redistribution as the dominant generation mechanism for zonal flows. The zonal flows modify the nonlinear dynamics of phase space zonal structures, which reduces the amount of EPs able to resonate with the mode, leading to a lower saturation amplitude. Simulation results including zonal flows agree quantitatively with DIII-D experimental measurements of the fishbone saturation amplitude and EP transport, supporting this novel saturation mechanism by self-generated zonal flows. Moreover, the wave-particle mode-locking mechanism is shown to determine quantitatively the fishbone frequency down-chirping, as evident in GTC simulation results in agreement with predictions from analytical theory. Finally, the fishbone-induced zonal flows are possibly responsible for the formation of an ion internal transport barrier (ITB) in the DIII-D discharge. Based on the low EP transport and the large zonal flow shearing rates associated with the fishbone instability in gyrokinetic simulations of the ITER scenario, it is conjectured that high performance scenarios could be designed in ITER burning plasmas through fishbone-induced ITBs.