bluuebunny/crossref_metadata_2025 huggingface dataset:
Psychiatrie in der DDR als „Nische“ –
Zwischen Anpassung und Freiraum
Authors: Windirsch Antonia , Reis Olaf , Grabe Hans Jörgen , Kumbier Ekkehardt
Published: November 2023

Zielstellung  Anhand von Zeitzeugenaussagen soll erschlossen
werden, ob und inwieweit die Institution Psychiatrie in der staatlich
kontrollierten Gesellschaft der DDR als Schutzraum oder „Nische“
für Mitarbeiter und Patienten erlebt wurde und welcher
Anpassungsleistungen es bedurfte, diese Räume möglichst autonom
gestalten zu können.

Methodik  Der Inhalt von 74
leitfadengestützten Interviews zur Psychiatrie in der DDR von
verschiedenen beruflichen Akteuren und ehemaligen Patienten wurde qualitativ
ausgewertet.

Ergebnisse  Aus den Interviews lässt sich
ableiten, dass die Psychiatrie in der DDR auch eine „Nische“
für Andersdenkende darstellte und einen gewissen Schutz für
Patienten bieten konnte. Demgegenüber steht die Verletzung des
Schutzraumes durch politische Einflussnahme bei der Patientenbehandlung sowie
strukturelle Missstände.

Schlussfolgerung  Psychiater in
der DDR nutzten auch kleine Möglichkeiten, um durch ihr Handeln
Patienten zu schützen. Unter diesen Bedingungen konnte die Psychiatrie
ein Ort des Schutzes für Patienten und Mitarbeiter darstellen. Die
Schaffung solcher Freiräume erforderte jedoch Anpassungsleistungen, die
ebenfalls von der Psychiatrie erbracht wurden. Umgekehrt wurde die Psychiatrie
auch politisch instrumentalisiert; entweder direkt durch ungerechtfertigte
Einweisungen und Ausgangsbeschränkungen oder indirekt, indem
Andersdenkende stigmatisiert und damit aus der Gesellschaft entfernt wurden.
Revisiting the ‘flexibility paradox’: degree of work schedule flexibility and time use patterns across gender and occupational groups
Authors: Lu Zhuofei , Wang Senhu , Olsen Wendy
Published: November 2023

Whether flexible work schedules facilitate the balance between work and non-work time or instead lead to longer working hours (known as ‘flexibility paradox’) has been extensively debated. Using representative time use data in the UK (2014–2015), this study contributes to the debates by exploring how different types of flexible schedules shape employees’ time use in various domains across gender and occupational groups. We find that using limited flexible schedules with fixed core hours (not unlimited flexible schedules) is significantly related to shorter paid work hours and more free time. The beneficial effects of limited flexible schedules only apply to men in higher occupations, whereas men in lower occupations are likely exploited by these flexible schedules by working more and having less free time. Overall, this study contributes to the debates of ‘flexibility paradox’ by examining the varying nature of flexibility practised and its different time use implications across socio-demographic groups.
Joint liability and aggravation? An inspection of legislative and judicial practices in cases of the crime of the abduction, sale, and purchase of women and children in China
Authors: Wang Dezheng
Published: November 2023

Human trafficking is a harmful, widespread and pressing issue that demands attention. However, the prevalence of such crimes may vary across different countries and time periods, which means that there may not be a universal solution to addressing them. In response to the recent public outcry sparked by the incident of the woman chained in Feng County, Xuzhou, this article provides a comprehensive review of China’s legislative and judicial responses to crimes against women and children who are abducted and sold, as well as the corresponding governance effects and causes. This study examines whether the punishment for buying and trafficking women and children should be increased through criminal law amendments and whether the current public outrage calling for equal punishment for buyers and sellers is justified. To provide a rational response to these issues, the article reviews all relevant laws, regulations, judicial cases, and typical cases from 1979 to 2022. An analysis of the change in case processing over the years was conducted using MATLAB software with the baseline panel regression model, robustness checks, and mechanism tests. This study reveals a decline on human trafficking crimes in China, but four provinces (Yunnan, Henan, Shandong, and Fujian) have a higher incidence. The article offers a comprehensive analysis from both macro and micro perspectives. National macro factors such as economic development, social welfare policies, rural revitalization, and COVID-19 prevention contribute to the decline. From a micro perspective, local differences in these provinces are a significant reason for high incidence from a micro perspective. This article suggests that legal amendments to increase punishment would be ineffective. Instead, existing legal provisions should be applied, and decision-making rules from typical cases should be utilized.
Political media use, civic knowledge, civic self-efficacy, and gender: measuring active citizenship in Turkey
Authors: Arslan Hakan , Yazıcı Sedat , Çetin Ensar , Dil Kemal , Çakır Fatma Sönmez
Published: November 2023

Despite many extensive and fruitful studies, assessing and analysing active citizenship behaviours in various cultural contexts remains a topic of research interest. A significant proportion of citizenship studies rely on evidence from adolescents, with their expected participation as the dependent variable rather than the actual civic engagement of adults. Prior research has also neglected to examine the internal civic self-efficacy of adult citizens, particularly concerning gender differences. Based on new data obtained from 731 Turkish citizens over eighteen, this study examines the effects of political media use, civic knowledge, civic self-efficacy, and gender, along with other demographic variables, on civic engagement and participation. We investigate research evidence that women’s tendency to interest in unconventional activities at a higher rate than men would make a difference and enhance their civic self-efficacy. Findings indicate that, at the empirical level, active citizenship is a multidimensional and interrelated concept with dimensions of civic knowledge, civic self-efficacy, engagement, and participation. Civic self-efficacy was found to be a psychological construct that predicts adult citizens’ active citizenship behaviours. Contrary to our hypothesis, gender differences in civic self-efficacy in community engagement closely related to daily life remain present, although women are expected to prefer greater participation than men. Only education indicated some equalising effect. Based on our findings, we suggest that research on citizenship should consider not only whether society values what women do, but also whether it promotes what they value.
A Δ-learning strategy for interpretation of spectroscopic observables
Authors: Watson Luke , Pope Thomas , Jay Raphael M. , Banerjee Ambar , Wernet Philippe , Penfold Thomas J.
Published: November 2023

Accurate computations of experimental observables are essential for interpreting the high information content held within x-ray spectra. However, for complicated systems this can be difficult, a challenge compounded when dynamics becomes important owing to the large number of calculations required to capture the time-evolving observable. While machine learning architectures have been shown to represent a promising approach for rapidly predicting spectral lineshapes, achieving simultaneously accurate and sufficiently comprehensive training data is challenging. Herein, we introduce Δ-learning for x-ray spectroscopy. Instead of directly learning the structure-spectrum relationship, the Δ-model learns the structure dependent difference between a higher and lower level of theory. Consequently, once developed these models can be used to translate spectral shapes obtained from lower levels of theory to mimic those corresponding to higher levels of theory. Ultimately, this achieves accurate simulations with a much reduced computational burden as only the lower level of theory is computed, while the model can instantaneously transform this to a spectrum equivalent to a higher level of theory. Our present model, demonstrated herein, learns the difference between TDDFT(BLYP) and TDDFT(B3LYP) spectra. Its effectiveness is illustrated using simulations of Rh L3-edge spectra tracking the C–H activation of octane by a cyclopentadienyl rhodium carbonyl complex.
Photodiode-based time zero determination for ultrafast electron microscopy
Authors: Kempers S. T. , Borrelli S. , Kieft E. R. , van Doorn H. A. , Mutsaers P. H. A. , Luiten O. J.
Published: November 2023

Pump-probe experiments in ultrafast electron microscopy require temporal overlap between the pump and probe pulses. Accurate measurements of the time delay between them allows for the determination of the time zero, the moment in time where both pulses perfectly overlap. In this work, we present the use of a photodiode-based alignment method for these time zero measurements. The cheap and easy-to-use device consists of a photodiode in a sample holder and enables us to temporally align individual, single-electron pulses with femtosecond laser pulses. In a first device, a temporal resolution of 24 ps is obtained, limited by the photodiode design. Future work will utilize a smaller photodiode with a lower capacitance, which will increase the temporal resolution and add spatial resolution as well. This upgrade will bring the method toward the micrometer and picosecond spatiotemporal resolution.
The laser-induced rearrangement of extended defects in crystalline CdTe at a low temperature
Authors: Krivobok V. S. , Nikolaev S. N. , Klokov A. Yu. , Sharkov A. I. , Chentsov S. I. , Usmanov I. I. , Mironchuk E. S.
Published: November 2023

The effect of subnanosecond laser pulses on the structure and electronic subsystem of extended defects in cubic semiconductors was studied using cadmium telluride (CdTe) as an example. A CdTe epitaxial film containing threading dislocations was exposed to pulsed laser emission at helium temperatures. This exposure led to a local rearrangement of dislocation, while the properties of the crystal lattice remained undisturbed. The rearrangement was visualized in situ via an observation of the single luminescent centers associated with the partial dislocation cores. The rearrangements in the center of the laser spot, as well as those far from this location, were detected, thus revealing the laser treatment’s non-thermal, relatively long-range influence. We associated the corresponding mechanism with Peierls’s gliding of dislocation under the impact of laser-induced hypersonic surface waves. The results we obtained are of interest in the development of all-optical methods for the local laser processing of extended defects in CdTe and subsequent expansion those methods to other A2B6 cubic semiconductors.
Hydrogen-mediated polarity compensation on the (110) surface terminations of ABO3 perovskites
Authors: Fung Victor , Hu Guoxiang , Wu Zili , Jiang De-en
Published: November 2023

Polar surfaces undergo polarity compensation, which can lead to significantly different surface chemistry from their nonpolar counterparts. This process in turn can substantially alter the binding of adsorbates on the surface. Here, we find that hydrogen binds much more strongly to the polar (110) surface than the nonpolar (100) surface for a wide range of ABO3 perovskites, forming a hydroxyl layer on the O24− termination and a hydride layer on the ABO4+ termination of the (110) surface. The stronger adsorption on the polar surfaces can be explained by polarity compensation: hydrogen atoms can act as electron donors or acceptors to compensate for the polarity of perovskite surfaces. The relative stability of the surface terminations is further compared under different gas environments and several perovskites have been found to form stable surface hydride layers under oxygen-poor conditions. These results demonstrate the feasibility of creating stable surface hydrides on perovskites by polarity compensation which might lead to new hydrogenation catalysts based on ABO3 perovskites.
Perspective on spin-based wave-parallel computing
Authors: Kohda Makoto , Seki Takeshi , Yuminaka Yasushi , Uemura Tetsuya , Kikuchi Keito , Salis Gian
Published: November 2023

Waves exhibit unique characteristics, such as diffraction and interference, which distinguishes them from the particle nature of electrons currently used for binary and sequential data processing and storage. In the solid state, wave properties can be found in electron spin waves in semiconductors or magnons in magnetic materials. These are useful for communication, processing and storage, and allow multiplexing of the information. Given this perspective, after introducing the information theory of wave-parallel computing and arguing the fundamental properties necessary for implementation with wave-based information carriers, we specifically examine how electron spin waves and magnons can be used as information carriers for processing and storage. Then, after explaining the fundamental physics of the electron spin wave based on the persistent spin helix state, we assess the potential of magnon-assisted magnetization switching for realizing the selective writing and reading of multiplexed information. Ferromagnet/semiconductor hybrid structures are emphasized as a platform for generating and controlling both electron spin waves and magnons. Interconversion among light helicity, electron spin waves and magnons is also discussed. Finally, we show several challenges and provide an outlook on the key steps that must be demonstrated for implementing spin-based wave-parallel computing.
Predicting reaction behavior of tethered polymers in shear flow
Authors: Nguyen Anh Hung , Kania Sagar , Oztekin Alparslan , Webb Edmund B.
Published: November 2023

Kinetics of force-mediated chemical reactions of end-tethered polymers with varying chain length N in varying shear rate flow γ̇ are explored via coarse-grained Brownian dynamics simulations. At fixed γ̇, force F along a polymer increases linearly with N as previously predicted; however, contrary to existing theory, the F(N) slope increases for N above a transition length that exhibits minimal dependence on γ̇. Force profiles are used in a stochastic model of a force-mediated reaction to compute the time for x percent of a polymer population to experience a reaction, tx. Observations are insensitive to the selected value of x in that tx data for varying N and γ̇ can be consistently collapsed onto a single curve via appropriate scaling, with one master curve for systems below the transition N (small N) and another for those above (large N). Different force scaling for small and large N results in orders of magnitude difference in force-mediated reaction kinetics as represented by the population response time. Data presented illustrate the possibility of designing mechano-reactive polymer populations with highly controlled response to flow across a range in γ̇.
Water–air acoustic communication based on broadband impedance matching
Authors: Zhou Ping , Jia Han , Bi Yafeng , Yang Yunhan , Yang Yuzhen , Zhang Peng , Yang Jun
Published: November 2023

Efficient acoustic communication across the water–air interface has always been expected in the field of ocean exploration. However, the existing research works are mainly concentrated on the narrow-band transmission based on resonance, which greatly limits the transmission capacity and efficiency. Here, we combined air-based and water-based metafluids to realize an exponential gradient impedance matching layer for broadband water–air sound transmission. By cooperatively adjusting the sound velocity and thickness in the matching layers, we modulated the required acoustic parameters of each layer into a reasonable range, which can be conveniently achieved by the proposed metafluids. A matching layer sample was constructed and validated in a water tank. Experimental results show that the proposed matching layer can achieve an average sound energy transmission enhancement above 16.7 dB from 880 to 1760 Hz across the water–air interface. A water–air acoustic communication scene was further experimentally demonstrated through transmitting a multicolor picture from air to water, which shows extremely high communication capacity and accuracy. Our work is promising for more applications based on water-air transmission and opens an avenue to the design and implementation of the extreme impedance matching case.
Cladding modulated silicon waveguide Bragg grating with TM-polarized light for optical true time delay line
Authors: Yoon Jinhyeong , Kim Jae-Yong , Kim Junhyeong , Hong Seokjin , Neseli Berkay , Park Joonyong , Park Hyo-Hoon , Kurt Hamza
Published: November 2023

An optical true time delay line (OTTDL) is an essential component in optical signal processing. A Bragg grating structure is usually employed in OTTDL design, which makes it possible to achieve a slow-light effect. Here, we present the design and experimental demonstration of a cladding modulated waveguide Bragg grating (CMWBG) that supports transverse magnetic polarization for OTTDL application. In contrast to traditional waveguide Bragg gratings that support transverse electric polarization, the proposed structure has low propagation loss and high fabrication tolerance characteristics. The slow-light effect of the CMWBG was experimentally demonstrated with a high group index value. An averaged maximum group delay value of up to 84.4 ps was achieved at a length of 1 mm CMWBG, and a tuning range of about 81.4 ps was obtained.
Surface scattering-dependent electronic transport in ultrathin scandium nitride films
Authors: Mukhopadhyay Debmalya , Rudra Sourav , Biswas Bidesh , Das Prasanna , Saha Bivas
Published: November 2023

With the constant miniaturization of device technologies, it has become essential to understand and engineer the electronic properties of semiconductors in nanoscale dimensions. Scandium nitride (ScN), an emerging rock salt indirect bandgap semiconductor, has attracted significant interest for its interesting thermoelectric, plasmonic, neuromorphic computing, and Schottky barrier device applications. However, an in-depth understanding of the electronic transport, carrier scattering mechanism, and optical properties in ultrathin ScN films is still missing. Here, we show surface-scattering dominant electronic transport in epitaxial ScN films at nanoscale thicknesses. At the ultrathin dimensions, surface scattering increases significantly due to the large surface-to-volume ratio and growth-induced texturing. As a result, mobility decreases, and resistivity increases drastically with decreasing film thickness. Temperature-dependent electronic transport shows that the mobility of the ultrathin films decreases with increasing temperature due to the ionized-impurity and dislocation scattering. Electronic transport properties are further rationalized with x-ray diffraction and pole-figure analysis that shows that while the ultrathin films maintain their predominant 002 texture, their quality degrades with decreasing thickness. However, no significant changes are observed in the electronic structure of the films, as evidenced by x-ray photoelectron spectroscopy, photoemission measurements, and first-principles density functional theory calculations. Our results elucidate the impact of surface scattering on the ultrathin ScN films and would lead to miniaturized devices with improved efficiencies.
Characterization of cavitation zone in cavitating venturi flows: Challenges and road ahead
Authors: Vijayan Anuja , P Pradeep Kumar
Published: November 2023

Dynamic features of a cavitating venturi have been a topic of investigation for the past few decades. This review presents state-of-the-art of experimental and numerical studies in cavitating venturi to address the challenges in understanding flow behavior and developing reliable numerical models. Many experimental studies have shown that two strongly coupled mechanisms, namely, Re-entrant Jet and the bubbly shock influence the cavitation zone behavior. We provide pointers from the past and recent studies to the influence of geometry and operating conditions, introducing changes in cavity oscillation. From an operational viewpoint, the modeling studies need to predict four crucial parameters related to its steady and dynamic operation: choked mass flow rate, operating pressure ratio range, cavitation length, and frequency of cavity oscillations. In this paper, we discuss the possible ways to properly configure a one-dimensional (1D) model, which can be a handy tool for extracting the key integral parameters. Realistic predictions require direct numerical simulations, which is not always an economically viable option. Recent three-dimensional (3D) simulations with compressible formulations for flow field and a cavitation model coupled with large eddy simulations to handle turbulence have achieved some success in predictions. Many simplified approaches have been popular. In this paper, we systematically bring out the predictability limits of popularly used mixture models coupled with cavitation and turbulence in more commonly studied two-dimensional (2D) and fewer three-dimensional geometries. Two-fluid models could provide answers, but further studies are required to mitigate the modeling challenges and to enable realistic predictions of the steady and dynamic features of this elegant flow control device for a chosen application.
Improving water removal efficiency in a PEM fuel cell: Microstructured surfaces for controlling instability-driven pinching
Authors: Mondal Nilanjan , Biswas Diptesh , Bakli Chirodeep
Published: November 2023

Proton Exchange Membrane Fuel Cell (PEMFC) is a clean, sustainable energy generation device, and its large-scale usage is becoming popular due to green and secure energy demand worldwide. The performance, efficiency, and lifespan of PEMFC largely depend on the water removal and management within the cell. Under the influence of the cross-air flow, the generated water filaments deform, and as the filament radius lowers, the curvature and capillary pressure increase, ejecting fluid out of the neck at increasing velocities. The moment the filament radius vanishes, the governing equations reach the point of singularity, and the filament breaks. We propose an optimum micro-patterned surface design for efficient water removal from PEMFC. We perform a numerical study of water generation on the surface followed by breakup under shear flow within confinement. We further theoretically identify the breakup behavior with characterization, recognizing the influence of the microstructures toward an efficient design. The hydrophobic microstructures are observed to decrease the dominance of viscous force over inertia and capillary force. This leads to a greater propensity of end-pinching or truncation of the generated droplet at the neck, which reduces the production of undesired satellite droplets that would have otherwise caused flooding of the chamber. In this work, we show that a proper combination of substrate structure and jet velocity-induced shear can mitigate the generation of satellite droplets and reduce the breakup time, significantly increasing the water removal efficiency of the PEMFC.
Multistability, period-adding, and fractality in a plasma oscillator
Authors: Recco Abel A. C. , Sagás Julio C. , Rech Paulo C.
Published: November 2023

In this paper, we report on a periodically driven plasma oscillator modeled by a six-parameter nonhomogeneous second-order ordinary differential equation. We fix four of these parameters, and investigate the dynamics of this system by varying the other two, namely, the amplitude A and the angular frequency ω of the driving. In other words, we investigate the (ω,A) parameter plane, where the dynamical behavior of each point was characterized by the magnitude of the largest Lyapunov exponent. Then, we show that this parameter plane reveals the occurrence of the multistability phenomenon in the system. Properly generated bifurcation diagrams confirm this finding. Basins of attraction of coexisting periodic and chaotic attractors in the phase-space are presented. We also report on the organization of periodicity and chaos in the (ω,A) parameter plane. Typical periodic structures were detected embedded in a chaotic region, namely, the cuspidal, the non-cuspidal, and the shrimp-like. At a certain location on the parameter plane, the organization of the shrimp-like periodic structures resembles a fractal, since the same shape is seen when we look through different scales. Elsewhere these same structures appear organized in a period-adding sequence.
Performance assessment of hybrid PEMFC-solar energy integrated hybrid multi-generation system for energy production sport buildings
Authors: Kethineni Balakrishna , Muda Iskandar , Prodanova Natalia , Askar Shavan , Abdullaev Sherzod , Shamel Ali , Mikaeilvand Nasser
Published: November 2023

Polymer membrane electrolyzers are a useful tool for producing hydrogen, which is a renewable energy source. Unmanned aerial vehicle (UAV) fuel cells can be powered by the hydrogen and oxygen produced by the electrolyzer. The primary losses of polymer membrane electrolyzers must therefore be identified in order to maximize their performance. A renewable-based multi-energy system considers power, cooling, heating, and hydrogen energy as utility systems for integrated sport buildings. In this study, we investigate the effect of radiation intensity, current density, and other performance factors on the rate of hydrogen production in water electrolysis using a polymer membrane electrolyzer in combination with a solar concentrator. The findings showed that a rise in hydrogen generation led to an increase in current density, which increased the electrolyzer’s voltage and decreased its energy and exergy efficiencies. The voltage was also increased, and the electrolyzer’s efficiency was enhanced by a rise in temperature, a decrease in pressure, and a reduction in the thickness of the nafion membrane. Additionally, with a 145% increase in radiation intensity, hydrogen production increased by 110% while the electrolyzer’s energy and exergy efficiencies decreased by 13.8% as a result of the electrolyzer’s high input electric current to hydrogen output ratio.
Thickness-dependent carrier polarity of MoTe2 transistors with NiTe2 semimetal contacts
Authors: Di Boyuan , Wen Xiaokun , Lei Wenyu , Zhang Yuhui , Li Liufan , Xu Xinyue , Kong Wenchao , Chang Haixin , Zhang Wenfeng
Published: November 2023

We demonstrated that the carrier polarity of MoTe2 transistors can be modulated by controlling the channel thickness with NiTe2 semimetal contacts. The multilayer MoTe2 transistors (thickness >7.1 nm) exhibit a symmetric ambipolar conduction, and a transition to unipolar p-type polarity occurs as the channel thickness decreased down to ∼2.3 nm. The position of the semimetal NiTe2 work function was verified to be located at the mid-gap of multilayer MoTe2, and the observed transition was interpreted by a synergistic effect of the channel thickness-dependent band alignment and charge transfer behavior with unique NiTe2 semimetal contacts.
Experimental evidence of the oscillation behavior of the interlayer DMI effect
Authors: Gao F. S. , Liu S. Q. , Zhang R. , Xia J. H. , He W. Q. , Li X. H. , Luo X. M. , Wan C. H. , Yu G. Q. , Su G. , Han X. F.
Published: November 2023

Chiral spin interactions play an important role in magnetism. Recent reports have revealed a new type of antisymmetric and indirect spin interaction, namely, the interlayer Dzyaloshinskii–Moriya interaction (DMI), which is predicted to arise from the three-site spin–orbit scattering of delocalized electrons as an additional Ruderman–Kittel–Kasuya–Yosida (RKKY) effect. Here, we investigated the interlayer DMI and RKKY interaction in the similar Pt/Co/Pt/Ru/Pt/Co/Pt structures as a function of spacer thickness. Both interactions present a synchronous damping oscillation and support the predicted relevance between them. The coupling strength of the interlayer DMI was finely engineered by tunning thickness of the nonmagnetic spacer. This work can deepen the understanding of the interlayer DMI and guide the control and use of the interlayer DMI in the field-free spin–orbit torque switching or the design of three-dimensional chiral spin textures.
Cell-type-specific optogenetic stimulation of the locus coeruleus induces slow-onset potentiation and enhances everyday memory in rats
Authors: Tse Dorothy , Privitera Lucia , Norton Anna C. , Gobbo Francesco , Spooner Patrick , Takeuchi Tomonori , Martin Stephen J. , Morris Richard G. M.
Published: November 2023

Memory formation is typically divided into phases associated with encoding, storage, consolidation, and retrieval. The neural determinants of these phases are thought to differ. This study first investigated the impact of the experience of novelty in rats incurred at a different time, before or after, the precise moment of memory encoding. Memory retention was enhanced. Optogenetic activation of the locus coeruleus mimicked this enhancement induced by novelty, both when given before and after the moment of encoding. Optogenetic activation of the locus coeruleus also induced a slow-onset potentiation of field potentials in area CA1 of the hippocampus evoked by CA3 stimulation. Despite the locus coeruleus being considered a primarily noradrenergic area, both effects of such stimulation were blocked by the dopamine D1/D5 receptor antagonist SCH 23390. These findings substantiate and enrich the evidence implicating the locus coeruleus in cellular aspects of memory consolidation in hippocampus.
Temperature dependence of narrow-band UVB photoluminescence of silica–(Gd,Pr)PO4 transparent glass-ceramic phosphors
Authors: Kajihara Koichi , Nakagawa Shingo , Nakagawa Ryosui , Suda Mayu , Ishijima Masanao , Kuriyama Haruo , Serizawa Izumi
Published: November 2023

The effect of temperature on photoluminescence (PL) due to the 6P
j
→ 8S7/2 (j = 5/2, 7/2) transitions of Gd3+ ions was examined between 200 and 500 K for a sol–gel-derived silica–(Gd,Pr)PO4 transparent glass-ceramic phosphor with negligible concentration quenching under excitation into the 5d–4f transition of Pr3+ ions at 220 nm. The intensity of the narrow-band ultraviolet B (UVB) PL at ∼313 nm associated with the 6P7/2 → 8S7/2 transition slightly increased between 200 and 300 K, but was decreased to ∼86% and ∼62% of that at 300 K when temperature was raised to 400 and 500 K, respectively. The observed magnitude of the thermal quenching of the UVB PL intensity was agreed well with that recorded in a prototype narrow-band UVB lamp consisting of another silica–(Gd,Pr)PO4 transparent glass-ceramic window and a KrCl excimer lamp as a light source at 222 nm. The silica–(Gd,Pr)PO4 transparent glass-ceramics was more resistant to the thermal quenching of the narrow-band UVB PL than a conventional powder phosphor, probably because of the encapsulation of (Gd,Pr)PO4 nanocrystals with low quenching centre concentrations in inert silica glass matrix.
A sub-millimetre two-wavelength EDM that compensates the air refractive index: uncertainty and measurements up to 5 km
Authors: Guillory Joffray , Truong Daniel , Wallerand Jean-Pierre , Alexandre Christophe
Published: November 2023

Distance measurements over several kilometres with a sub-millimetre uncertainty are required for deformation monitoring in fields such as geodesy or civil engineering where well-controlled scale is critical. This paper presents a two-wavelength electro-optical distance meter (EDM) capable of such measurements and traceable to the SI (Système International d’unités). It is based on simultaneous measurements of optical path lengths, at two wavelengths, one at 780 nm and the other at 1560 nm, the dispersion between the two wavelengths allowing real-time compensation of the air refractive index along the optical paths. The uncertainty budget of this EDM has been established, taking into account both the telemetric and the mechanical contributions. One of the main sources of errors is crosstalk, which originates mainly from the optical splitters acting as circulators and becomes more pronounced for lower received powers over longer distances. For signal-to-crosstalk ratios (SCRs) higher than 60 dB, the instrumental uncertainty in the air-index compensated distance was assessed to be 320 µm (k = 1). In the field, two distance measurements, one over 2.6 km, the other over 5.4 km, were carried out over a period of up to 6 days, and for a temperature and pressure varying by as much as 10 °C and 17 hPa. For each distance, the standard deviation of the Gaussian fit of the experimental points was less than 250 µm. This level of refractivity compensation demonstrates that the developed instrument works properly. In addition, standard deviations lower than 140 µm were achieved for displacement measurements at distances around 2.6 km and 5.4 km. All these results were obtained for SCRs higher than 60 dB. Finally, solutions are proposed for mitigating the effect of high crosstalk values on instrumental uncertainty.
A probabilistic-phase field model for the fracture of brittle materials
Authors: Alabdullah Mohammad , Ghoniem Nasr M
Published: November 2023

We develop a computational method to determine the failure probability of brittle materials under general mechanical loading conditions. The method is a combination of two parts: (1) numerical simulations of materials with multiple cracks using phase field theory, where the complete fracture process is viewed as ‘damage percolation’ along critical paths or clusters of cracks, rather than the traditional weak-link failure mechanism of Weibull, and (2) an extension of the Batdorf statistical theory of fracture to finite domains, where it is implemented within the finite element framework. The results of phase-field simulations at the ‘percolation threshold’ are used as failure data in the Batdorf theory to determine the overall probability of failure. The input to this approach is the size distribution of cracks in a pristine material. An example is shown, where alumina samples that were previously tested by Abe and coworkers (Abe et al 2003 J. Am. Ceram. Soc.
86 1019–21) in four-point loading are compared to the results of our numerical simulations. The approach developed here has the advantage of being extendable to more complex thermomechanical loading.
MAUNext: a lightweight segmentation network for medical images
Authors: Wang Yuhang , Wang Jihong , Zhou Wen , Liu Zijie , Yang Chen
Published: November 2023

Objective. The primary objective of this study is to enhance medical image segmentation techniques for clinical research by prioritizing accuracy and the number of parameters. Approach. To achieve this objective, a novel codec-based MAUNext approach is devised, focusing on lightweight backbone design and the integration of skip connections utilizing multiscale, attention mechanism, and other strategic components. The approach is composed of three core modules: a multi-scale attentional convolution module for improved accuracy and parameter reduction, a collaborative neighbourhood-attention MLP encoding module to enhance segmentation performance, and a tiny skip-connected cross-layer semantic fusion module to bridge the semantic gap between encoder and decoder. Main results. The study extensively evaluates the MAUNext approach alongside eight state-of-the-art methods on three renowned datasets: Kagglelung, ISIC, and Brain. The experimental outcomes robustly demonstrate that the proposed approach surpasses other methods in terms of both parameter numbers and accuracy. This achievement holds promise for effectively addressing medical image segmentation tasks. Significance. Automated medical image segmentation, particularly in organ and lesion identification, plays a pivotal role in clinical diagnosis and treatment. Manual segmentation is resource-intensive, thus automated methods are highly valuable. The study underscores the clinical significance of automated segmentation by providing an advanced solution through the innovative MAUNext approach. This approach offers substantial improvements in accuracy and efficiency, which can significantly aid clinical decision-making and patient treatment.
Decrypting the thermal effects on the electric field-induced material formation process on Cr thin films
Authors: Ghosh Swapnendu Narayan , Talukder Santanu
Published: November 2023

Controlled electrochemical reactions on chromium (Cr) thin films have been employed to create micro- and nano-scale patterns using a scanning probe-based patterning process called electrolithography (ELG). The electrochemical reaction produces a liquid material. The ELG process, being a local anodic oxidation-based technique, is significantly affected by several factors, including various ambient conditions. In this article, we explore the effects of temperature on the said electrochemical reaction-induced liquid material formation process. Keeping other ambient conditions constant, the temperature is varied over a large range, and we observe that a 40 °C change in temperature results in a 20-time change in the radial spread of the liquid region. This observation is thereafter explained by the effect of temperature on three different parameters affecting the rate of electrochemical reaction. Thus, based on this study, we can say that temperature is one of the most crucial parameters which can be used to confine the lateral spread of the formed liquid region and thereby improve the resolution of the patterns created using the ELG technique.
Atmospheric-pressure CVD-grown h-BN for the detector with deep ultraviolet response
Authors: Yang Yufei , Sun Wenhong
Published: November 2023

Hexagonal boron nitride (h-BN) has a wide range of applications, especially as a protective coating, dielectric layer/substrate, transparent film, or deep ultraviolet detectors. High-quality h-BN thick films are indispensable for practical deep-ultraviolet (DUV) photodetector applications. However, the controlled synthesis of h-BN films in terms of thicknesses and crystallinity often requires high growth temperatures, low pressures, and catalytic transition metal substrates, which will ultimately hinder their applicability. In this work, we conducted a detailed study of h-BN films with thickness ranging from 50 nm to 160 nm directly synthesized by chemical vapor deposition (CVD) on SiO2/Si substrate under atmospheric pressure. The synthesized h-BN is clean, uniform, and exhibits excellent optical and photoelectrical properties for ultraviolet light in the range of 210 nm-280 nm. This sensitive h-BN photodetector has a high repulsion rate (R220nm/R280nm > 102 and R220nm/ R290nm > 103), a large detection rate (2.8 × 1010 Jones). This work presented here demonstrates the great potential of this h-BN thick film for the development of DUV photodetectors.
Super-flat coherent mid-infrared supercontinuum in all-normal dispersion As39Se61 chalcogenide photonic crystal fiber
Authors: Yang Xinyu , Yang Jian , Xu Qibo , Yang Hua
Published: November 2023

We numerically demonstrated the generation of super-flat coherent mid-infrared supercontinuum in all-normal dispersion (ANDi) As39Se61 chalcogenide photonic crystal fiber (PCF). The PCF with flat-ANDi and high nonlinearities is obtained by optimizing the structural parameters of the fiber. When pumping a 50 fs pulse width and 6 kW peak power laser pulses at 3.35 μm, under 3dB spectral flatness the super-flat coherent mid-infrared supercontinuum extended from 2.17 to 7.47 μm is obtianed. Such coherent mid-infrared supercontinuum are enormously required for optical coherence tomography, biological imaging and frequency metrology.
Reheating after inflaton fragmentation
Authors: Garcia Marcos A.G. , Pierre Mathias
Published: November 2023

In the presence of self-interactions, the post-inflationary evolution of the inflaton field is driven into the non-linear regime by the resonant growth of its fluctuations. The once spatially homogeneous coherent inflaton is converted into a collection of inflaton particles with non-vanishing momentum. Fragmentation significantly alters the energy transfer rate to the inflaton's offspring during the reheating epoch. In this work we introduce a formalism to quantify the effect of fragmentation on particle production rates, and determine the evolution of the inflaton and radiation energy densities, including the corresponding reheating temperatures. For an inflaton potential with a quartic minimum, we find that the efficiency of reheating is drastically diminished after backreaction, yet it can lead to temperatures above the big bang nucleosynthesis limit for sufficiently large couplings. In addition, we use a lattice simulation to estimate the spectrum of induced gravitational waves, sourced by the scalar inhomogeneities, and discuss detectability prospects. We find that a Boltzmann approach allows to accurately predict some of the main features of this spectrum.
Cosmological coupling of nonsingular black holes
Authors: Cadoni M. , Sanna A.P. , Pitzalis M. , Banerjee B. , Murgia R. , Hazra N. , Branchesi M.
Published: November 2023

We show that — in the framework of general relativity (GR) — if black holes (BHs) are singularity-free objects, they couple to the large-scale cosmological dynamics. We find that the leading contribution to the resulting growth of the BH mass (M
BH) as a function of the scale factor a stems from the curvature term, yielding M
BH ∝ ak
, with k = 1. We demonstrate that such a linear scaling is universal for spherically-symmetric objects, and it is the only contribution in the case of regular BHs. For nonsingular horizonless compact objects we instead obtain an additional subleading model-dependent term. We conclude that GR nonsingular BHs/horizonless compact objects, although cosmologically coupled, are unlikely to be the source of dark energy.
We test our prediction with astrophysical data by analysing the redshift dependence of the mass growth of supermassive BHs in a sample of elliptical galaxies at redshift z = 0.8–0.9. We also compare our theoretical prediction with higher redshift BH mass measurements obtained with the James Webb Space Telescope (JWST). We find that, while k = 1 is compatible within 1σ with JWST results, the data from elliptical galaxies at z = 0.8–0.9 favour values of k > 1. New samples of BHs covering larger mass and redshift ranges and more precise BH mass measurements are required to settle the issue.
Ultrafast nonlinear absorption in MoTe2 and MoTe2/MoS2 nanocomposite films and its application to all-optical logic gates
Authors: Saifi Anam , Roy Sukhdev
Published: November 2023

We present a detailed theoretical analysis of ultrafast saturable absorption (SA) and reverse SA (RSA) in MoTe2 nano-films with femtosecond (fs) laser pulses at 800 nm. A transition from RSA to SA occurs on increasing the thickness from 30 nm to 80 nm at a constant pump intensity of 141 GW cm−2. On the other hand, a transition from SA to RSA occurs upon increasing the pump intensity in an 80 nm thick MoTe2 nano-film. Theoretical results are in good agreement with reported experimental results. The effect of pump pulse intensity, pulse width, nonlinear absorption coefficient and sample thickness has been studied to optimize the SA ↔ RSA transition. The results for low-power and high contrast all-optical switching in MoTe2 nano-films have been used to design all-optical fs NOT, OR, AND, as well as the universal all-optical NOR and NAND logic gates. The SA behavior of MoTe2/MoS2 nanocomposite films has been used to design all-optical AND and OR logic gates. The nanocomposite films of MoTe2/MoS2 possess a larger nonlinear optical response in comparison to MoTe2 and MoS2 nano-films and, therefore, all-optical logic gates designed using nanocomposite films result in a good switching contrast compared to pure MoTe2 nano-films. Ultrafast operation at relatively low pump intensities demonstrates the applicability of MoTe2 and MoTe2/MoS2 nano-films for ultrafast all-optical information processing.
Effect of cognitive training on brain dynamics
Authors: Lv 吕 Guiyang 贵阳 , Xu 徐 Tianyong 天勇 , Chen 陈 Feiyan 飞燕 , Zhu 朱 Ping 萍 , Wang 王 Miao 淼 , He 何 Guoguang 国光
Published: November 2023

The human brain is highly plastic. Cognitive training is usually used to modify functional connectivity of brain networks. Moreover, the structures of brain networks may determine its dynamic behavior which is related to human cognitive abilities. To study the effect of functional connectivity on the brain dynamics, the dynamic model based on functional connections of the brain and the Hindmarsh–Rose model is utilized in this work. The resting-state fMRI data from the experimental group undergoing abacus-based mental calculation (AMC) training and from the control group are used to construct the functional brain networks. The dynamic behavior of brain at the resting and task states for the AMC group and the control group are simulated with the above-mentioned dynamic model. In the resting state, there are the differences of brain activation between the AMC group and the control group, and more brain regions are inspired in the AMC group. A stimulus with sinusoidal signals to brain networks is introduced to simulate the brain dynamics in the task states. The dynamic characteristics are extracted by the excitation rates, the response intensities and the state distributions. The change in the functional connectivity of brain networks with the AMC training would in turn improve the brain response to external stimulus, and make the brain more efficient in processing tasks.
Broadband bidirectional Brillouin–Raman random fiber laser with ultra-narrow linewidth
Authors: Yang 杨 Qian 茜 , Li 李 Yang 阳 , Zou 邹 Hui 辉 , Mei 梅 Jie 杰 , Xu 徐 En-Ming 恩明 , Zhang 张 Zu-Xing 祖兴
Published: November 2023

We present a Brillouin–Raman random fiber laser (BRRFL) with full-open linear cavity structure to generate broadband Brillouin frequency comb (BFC) with double Brillouin-frequency-shift spacing. The incorporation of a regeneration portion consisting of an erbium-doped fiber and a single-mode fiber enables the generation of broadband BFC. The dynamics of broadband BFC generation changing with the pump power (EDF and Raman) and Brillouin pump (BP) wavelength are investigated in detail, respectively. Under suitable conditions, the bidirectional BRRFL proposed can produce a flat-amplitude BFC with 40.7-nm bandwidth ranging from 1531 nm to 1571.7 nm, and built-in 242-order Brillouin Stokes lines (BSLs) with double Brillouin-frequency-shift spacing. Moreover, the linewidth of single BSL is experimentally measured to be about 2.5 kHz. The broadband bidirectional narrow-linewidth BRRFL has great potential applications in optical communication, optical sensing, spectral measurement, and so on.
Fast compressed sensing spectral measurement with adaptive gradient multiscale resolution
Authors: Lan 蓝 Ruo-Ming 若明 , Liu 刘 Xue-Feng 雪峰 , Li 李 Tian-Ping 天平 , Bai 白 Cheng-Jie 成杰
Published: November 2023

We propose a fast, adaptive multiscale resolution spectral measurement method based on compressed sensing. The method can apply variable measurement resolution over the entire spectral range to reduce the measurement time by over 75% compared to a global high-resolution measurement. Mimicking the characteristics of the human retina system, the resolution distribution follows the principle of gradually decreasing. The system allows the spectral peaks of interest to be captured dynamically or to be specified a priori by a user. The system was tested by measuring single and dual spectral peaks, and the results of spectral peaks are consistent with those of global high-resolution measurements.