bluuebunny/crossref_metadata_2025 huggingface dataset:
Is visual content modality a limiting factor for social capital? Examining user engagement within Instagram-based brand communities
Authors: Kusuma Agung Artha , Afiff Adi Zakaria , Gayatri Gita , Hati Sri Rahayu Hijrah
Published: January 2024

In the age of virtual cocreation of value by consumers, the role of the content modality in the development of social capital has been largely overlooked. Given that different modalities lead to varied forms of digital communication, this study examines whether a predominantly visual modality can enhance social capital and improve the collective value perceived by members of an online brand community. Through quantitative analysis, this study demonstrates that the visual modality of Instagram fosters social interactions, shaping the platform’s engagement dynamics. Affect-based visual imagery is persuasive in eliciting responses that match the hedonic nature of the platform. Therefore, fostering a positive emotional connection to both the community and the brand can lead to increased loyalty. This research proposes a different perspective on the interactive social exchange that facilitates the establishment of social capital. Value cocreation engagement is not necessarily dependent on the extensiveness of information depth. Adopting an affective orientation in persuasion has shown efficacy in forming attitudes towards attitudinal objects, particularly the community and brand.
Phase change plasmonic metasurface for dynamic thermal emission modulation
Authors: Wang Zexiao , Jing Lin , Liu Xiu , Luo Xiao , Yun Hyeong Seok , Li Zhuo , Shen Sheng
Published: January 2024

Plasmonic metasurfaces with adjustable optical responses can be achieved through phase change materials (PCMs) with high optical contrast. However, the on–off behavior of the phase change process results in the binary response of photonic devices, limiting the applications to the two-stage modulation. In this work, we propose a reconfigurable metasurface emitter based on a gold nanorod array on a VO2 thin film for achieving continuously tunable narrowband thermal emission. The electrode line connecting the center of each nanorod not only enables emission excitation electrically but also activates the phase transition of VO2 beneath the array layer due to Joule heating. The change in the dielectric environment due to the VO2 phase transition results in the modulation of emissivity from the plasmonic metasurfaces. The device performances regarding critical geometrical parameters are analyzed based on a fully coupled electro-thermo-optical finite element model. This new metasurface structure extends the binary nature of PCM based modulations to continuous reconfigurability and provides new possibilities toward smart metasurface emitters, reflectors, and other nanophotonic devices.
Spacetime quasiperiodic solutions to a nonlinear Schrödinger equation on Z
Authors: Kachkovskiy Ilya , Liu Wencai , Wang Wei-Min
Published: January 2024

We consider a discrete non-linear Schrödinger equation on Z and show that, after adding a small potential localized in the time-frequency space, one can construct a three-parametric family of non-decaying spacetime quasiperiodic solutions to this equation. The proof is based on the Craig–Wayne–Bourgain method combined with recent techniques of dealing with Anderson localization for two-dimensional quasiperiodic operators with degenerate frequencies.
Use of an optical profilometer to measure the aerodynamic shape and the twist of a wind turbine blade
Authors: Torres-Moreno Eduardo , Moreno-Oliva Víctor Iván , Campos-García Manuel , Dorrego-Portela José Rafael , Lastres-Danguillecourt Orlando , Farrera-Vázquez Neín
Published: January 2024

This study introduces a metrological approach to measure the aerodynamic shape and the twist of a wind turbine blade. The optical profilometer measurement technique used is laser triangulation. A camera records the image of a line projected onto a section of the blade and, by reconstructing the airfoil shape, the twist angular position of the profile with respect to the axial line of the blade is determined. This methodology is applied to test different sections of a Wortmann FX 63-137 airfoil with a length of 1700 mm. The results of the aerodynamic shape and twist angle are quantitatively verified by comparing them with the ideal or design values. The reconstruction process achieved a resolution of 0.06 mm, and measurement errors in the twist angular position were less than 0.1°. The presented method is efficient, accurate, and low cost to evaluate the blade profiles of low-power wind turbines. However, due to its easy implementation, it is expected to be able to measure any full-scale wind blade profile up to several meters in length.
Experimental observation of two-dimensional phase in compressed FeF2
Authors: Hao Yinqiao , Lu Wencheng , Zhang Junkai , Zhou Mi , Liu Guangtao , Wang Hongbo
Published: January 2024

Iron difluoride (FeF2) has attracted considerable attention for its physical characteristics and practical applications, and its compression behaviors usually play a key role in the in-depth understanding of this compound. Since its high-pressure crystal structure evolution determining a more profound comprehension remains disputable, we carried out extensive experiments to focus on the pressure-induced structural phase transitions of FeF2. Through in situ high-pressure synchrotron x-ray diffraction measurements, we not only confirmed a reported high-pressure orthorhombic Pbca phase at 11 GPa but also identified an interesting two-dimensional structure with hexagonal close packed symmetry (P-3m1) that appears above 25 GPa at room temperature. Furthermore, the spontaneous strain fitting and electronic transport measurements suggest that its ambient rutile-type structure (P42/mnm) evolves into an orthorhombic structure (Pnnm) through a second-order phase transition at 5 GPa. These experimental results elaborate on the pressure-induced phase transitions of FeF2 on the order of P42/mnm → Pnnm → Pbca → P-3m1, shedding light on a rare three-dimensional to two-dimensional configuration transition in difluorides.
Five-view three-dimensional reconstruction for ultrafast dynamic imaging of pulsed radiation sources
Authors: Gao Jianpeng , Sheng Liang , Wang Xinyi , Zhang Yanhong , Li Liang , Duan Baojun , Zhang Mei , Li Yang , Hei Dongwei
Published: January 2024

Multiaxial neutron/x-ray imaging and three-dimensional (3D) reconstruction techniques play a crucial role in gaining valuable insights into the generation and evolution mechanisms of pulsed radiation sources. Owing to the short emission time (∼200 ns) and drastic changes of the pulsed radiation source, it is necessary to acquire projection data within a few nanoseconds in order to achieve clear computed tomography 3D imaging. As a consequence, projection data that can be used for computed tomography image reconstruction at a certain moment are often available for only a few angles. Traditional algorithms employed in the process of reconstructing 3D images with extremely incomplete data may introduce significant distortions and artifacts into the final image. In this paper, we propose an iterative image reconstruction method using cylindrical harmonic decomposition and a self-supervised denoising network algorithm based on the deep image prior method. We augment the prior information with a 2D total variation prior and a 3D deep image prior. Single-wire Z-pinch imaging experiments have been carried out at Qin-1 facility in five views and four frames, with a time resolution of 3 ns for each frame and a time interval of 40 ns between adjacent frames. Both numerical simulations and experiments verify that our proposed algorithm can achieve high-quality reconstruction results and obtain the 3D intensity distribution and evolution of extreme ultraviolet and soft x-ray emission from plasma.
Amorphous Ga2O3/GaN heterostructure for ultralow-energy-consumption optically stimulated synaptic devices
Authors: Han Xiaorui , Mo Youhan , Wang Yanbo , Yang Xiaoqin , Wang Jianyuan , Luo Bingcheng
Published: January 2024

Neuromorphic computing can transcend the existing performance-limiting conventional computing architectures (i.e., von Neumann paradigm) by designing biologically inspired devices with intelligence capabilities. Optically stimulated synaptic devices have recently emerged as an alluring direction in neuromorphic computing due to their combined sensing, memory, and computing functions. This study introduces a new two-terminal optically stimulated synaptic device based on an amorphous Ga2O3/GaN heterostructure. This III-nitride-compatible device exhibits persistent photoconductivity at broad ultraviolet wavelengths, enabling it to mimic essential biological synapse functions, including pair-pulse facilitation, short-term plasticity (STP), long-term plasticity (LTP), and STP-to-LTP transition. Furthermore, memory and learning capabilities are achieved in this device, with an ultralow energy consumption of 0.05 pJ per synaptic event, comparable to the human brain. This work presents a CMOS-compatible nitride synapse, suggesting potential applications in low-power computing.
Effect of chemical intercalation on ferroelectricity in van der Waals layered CuInP2S6
Authors: Feng Zhijian , Wang Shun , Zhou Zhou , Hu Yiqi , Li Qiankun , Xue Jinshuo , Yan Qingyu , Luo Zhongshen , Feng Runcang , Weng Yuyan , Fang Liang , You Lu
Published: January 2024

Chemical intercalation brings about intriguing opportunities to tailor the properties of van der Waals (vdW) layered materials by crafting molecular composite at an atomic scale. Despite a plethora of reports on various materials, the chemical intercalation effect on long-range ferroelectric order remains scarcely explored. Herein, we report the construction of hybrid supercrystal based on a model vdW ferroelectric, CuInP2S6 by molecular intercalation. Although the out-of-plane lattice structure remains commensurate, its ferroelectric polarization is largely destroyed by the chemical intercalation, as confirmed by combined piezoresponse microscopy and Raman spectroscopy. Alternatively, we observed a dipole glass transition at about 280 K by dielectric spectroscopy and correlated it with the Raman analysis. This work highlights the impact of chemical intercalation on collective ferroic orders and paves the routes for creating artificial hybrid crystals by incorporating functional molecules.
Computing probability density of the first passage time for state transition in stochastic dynamical systems driven by Brownian motions: A singular integral method
Authors: Sun Xu , Yang Fang , Sun Thomas
Published: January 2024

Nonlinear dynamical systems, such as climate systems, often switch from one metastable state to another when subject to noise. The first occurrence of such state transition, which is usually characterized by the first passage time, has gained enormous interest in many engineering and scientific fields. We develop an efficient numerical method to compute the probability density of the first passage time for state transitions in stochastic dynamical systems driven by Brownian motions. The proposed method involves solving a singular integral equation, which determines probability density of the first passage time. Some numerical examples, with application to a simplified thermohaline circulation system, are provided to illustrate and verify the proposed method.
Improvement of Ti/Al/Ti Ohmic contacts on AlGaN/GaN heterostructures by insertion of a thin carbon interfacial layer
Authors: Greco G. , Di Franco S. , Lo Nigro R. , Bongiorno C. , Spera M. , Badalà P. , Iucolano F. , Roccaforte F.
Published: January 2024

This Letter reports on the improvement of the morphological and electrical behavior in Ti/Al/Ti Ohmic contacts on AlGaN/GaN heterostructures by the insertion of a thin carbon interfacial layer. In particular, the presence of a carbon layer between the Ti/Al/Ti metal stack and the AlGaN surface leads to the lowering of the annealing temperature (down to 450 °C) required to obtain linear I–V curves and to the improvement of the contacts surface morphology. The temperature dependence of the specific contact resistance was explained by the thermionic field emission, with a reduction in the barrier height ΦB down to 0.62 eV in the annealed contacts with the interfacial carbon layer. The experimental evidence has been justified with the formation of a thin low work function TiC layer, which enhances the current conduction through the metal/AlGaN interface.
Carrier conduction mechanisms in MIS capacitors with ultra-thin Al2O3 at cryogenic temperatures
Authors: Rocha-Aguilera D. , Molina-Reyes J.
Published: January 2024

In this work, a study comprising the electrical characterization and analysis of the electrical response of metal–insulator–semiconductor Al/Al2O3/Si capacitors in a temperature range from ambient temperature down to 3.6 K is presented. An ultra-thin 6 nm Al2O3 film, deposited by atomic layer deposition, was used as an insulating layer. Current–voltage and electrical stress measurements were performed on the capacitors in the specified temperature range, and the experimental data obtained were analyzed using current transport equations to model the conduction mechanisms that allow charge transport through the Al2O3. Energetic parameters associated with trap levels within the Al2O3 bandgap corresponding to the Poole–Frenkel emission and trap-assisted tunneling mechanisms were obtained, and their temperature dependances were studied and associated with the presence of physical material defects. The analysis of the modeling results points to trap-assisted tunneling as the dominant mechanism at low temperatures for intermediate electric field values. Additional phenomena that limit charge transport were also observed, such as charge trapping in the bulk of the Al2O3 upon the application of electrical stress at ambient temperature and silicon freeze out at cryogenic temperatures. Our findings constitute an effort at understanding the physical phenomena that govern the electrical behavior of thin-film Al2O3-based capacitors, especially at cryogenic temperatures, given that these materials and devices are of considerable importance for applications in CMOS-based cryoelectronics and quantum technologies, among others.
Multistage smart radiator with gradient emittance based on phase change materials VO2/GST/IST
Authors: Xie Bowei , Zhang Shangyu , Zhang Wenjie , Zhao Junming , Liu Linhua
Published: January 2024

In this Letter, we present a multistage smart radiator with a gradient emittance that gradually increases with increasing temperature in the spectral range of 2.5–15 μm. Such smart radiator is a relatively simple multilayered structure composed of three phase change materials (PCMs): VO2, GST, and IST. The smart radiator achieves multistage manipulation of emittance through phase transitions of PCMs, with the largest emittance tunability of ∼0.85. The underlying mechanism involves manipulating the Fabry–Pérot resonance and antireflection. Additionally, the emittance is found to be relatively insensitive to polarization and incident angles. The proposed multistage smart radiator exposes excellent potential for exploitation in thermal management and energy conservation.
Thermionic enhanced heat transfer in x-ray tubes
Authors: Chen Suguo , Wang Pengtao , Zhang Xiaoqiuyan , Huang Sunchao , Wang Yue , Hu Min , Zhang Chao , Gong Yubin
Published: January 2024

Since their discovery in 1895, x-ray tubes have attracted enormous interest and have been intensively used in nondestructive inspection, medical imaging, and radiation therapy. However, the targets of x-ray tubes universally suffer from overheating problems since only 1% of the input energy is converted to x rays, and the remaining 99% is converted to heat. Thus, the overheating problem has severely restricted the development of high-power x-ray tubes. Here, we propose a method, e.g., thermionic cooling to enhance the heat transfer in x-ray tubes. By employing thermionic cooling, we found that the target temperature of x-ray tubes can be reduced from 1206 to 393 °C. Our results will pave the way for developing high-power x-ray tubes and, therefore, advance x-ray-based technologies.
Efficient photo-dissociation-induced production of hydrogen radicals using vacuum ultraviolet light from a laser-produced plasma
Authors: Hernandez James Edward , Tanaka Nozomi , Yamada Ryuya , Wang Yubo , Nishihara Katsunobu , Johzaki Tomoyuki , Sunahara Atsushi , Kang Kyung Sik , Ueyama Shinji , Ozawa Ken , Fujioka Shinsuke
Published: January 2024

One of the critical issues in lithography using extreme ultraviolet (EUV) light is tin contamination of the EUV collector mirrors in the tin-based LPP-EUV light source. The contamination can be removed by the reaction of tin atoms with hydrogen radicals producing stannane (SnH4), which is gaseous at the normal temperature. Hydrogen radicals can be produced from hydrogen molecules through photo-dissociation and photo-ionization induced by broadband radiation emitted from the EUV light source. In this work, an efficient production of hydrogen radical using vacuum ultraviolet (VUV) light emitted from laser-produced high-Z plasma is experimentally demonstrated. A two-dimensional radiation hydrodynamic simulation, coupled with photoionization and photo-dissociation cross sections, also shows the efficient hydrogen radical production by increased VUV light emission, as observed in the experiment.
Identification of stable QTLs and candidate genes associated with plant height and spike length in common wheat
Authors: Sardouei-Nasab Somayeh , Mohammadi-Nejad Ghasem , Nakhoda Babak
Published: January 2024

Context Plant height and spike length are important traits with significant impact on the potential yield of wheat. It is essential to dissect their genetic control in order to improve yield potential through breeding. Aims We aimed to identify genomic regions with stable and major-effect quantitative trail loci (QTLs) associated with plant height and spike length in common wheat (Triticum aestivum L.). Methods Three recombinant inbred line (RIL) mapping populations were created by crossing a common parental line, Roshan, with three different cultivars: Sabalan, Falat, and Superhead. The RILs were grown over 3 years at five locations under water-stressed and well-watered conditions. Plant height and spike length were measured during each experiment, and inclusive composite interval mapping was used to analyse the data in both single-and multi-environment analyses. Key results Single-environment analysis detected 32 additive QTLs in the three populations. Three novel, stable and non-epistatic QTLs were identified: qPH1D for plant height in the Sabalan background; and qSL1D and qSL1B.3 for spike length in the Falat and Superhead backgrounds, respectively. Between the flanking markers on chromosomes 1B, 1D and 4B, 191 genes were predicted, 20 of which were identified as potential candidates with roles in wheat plant height and spike-related traits. Conclusions The study identified stable QTLs for plant height and spike length in wheat, providing valuable markers for future breeding programs and enhancing yield potential. Implications These results lay a good foundation for fine mapping of QTLs/genes for molecular marker-assisted breeding in wheat in the future.
Photochemical attributes determine the responses of plant species from different functional groups of ferruginous outcrops when grown in iron mining substrates
Authors: Rios Camilla Oliveira , Pimentel Paulo Antônio , Bicalho Elisa Monteze , Garcia Queila Souza , Pereira Eduardo Gusmão
Published: January 2024

Environments originating from banded iron formations, such as the canga, are important reference ecosystems for the recovery of degraded areas by mining. The objective of this work was to evaluate if the relationship between morphofunctional and photosynthetic attributes of native canga species from different functional group results in distinct responses when grown in iron mining tailings substrate. The experiment was carried out with species belonging to different functional groups: a widespread semi-deciduous tree-shrub, Myrcia splendens; an endemic deciduous shrub, Jacaranda caroba; and a nitrogen-fixing herbaceous species, Periandra mediterranea. The species were grown in two conditions, reference soil and iron ore tailing. Despite belonging to different functional groups when grown in tailings, the morphofunctional attributes presented similar responses between species. M. splendens was the species most affected by the conditions imposed by the iron ore mining tailings, with decreased light-use efficiency and electron transport. P. mediterranea had satisfactory growth and maintenance of photosynthetic attributes. J. caroba growing in the tailings increased the effective quantum yield of PSII. The photochemical and growth assessments were able to better explain the adaptive strategies developed by the species, guaranteeing a greater chance of success during the rehabilitation of mining substrates.
Photonic reservoir computing for energy efficient and versatile machine learning application
Authors: Lüdge Kathy
Published: January 2024

Time-multiplexed reservoir computing is a machine learning concept which can be realised in photonic hardware systems using only one physical node. The concept can be used for various problems, ranging from classification problems to time-series prediction tasks, while being fast and energy efficient. Here, a theoretical analysis of a reservoir computer realised via delay-coupled semiconductor lasers is presented and the role of the internal system time-scales and the bifurcation structure is discussed. It is further shown that optimal performance can be reached by tailoring the coupling delays to the specific memory requirements of the given task.
Targeting the PHF8/YY1 axis suppresses cancer cell growth through modulation of ROS
Authors: Wu Xiao-Nan , Li Jia-yuan , He Qi , Li Bo-qun , He Yao-hui , Pan Xu , Wang Ming-yue , Sang Rui , Ding Jian-cheng , Gao Xiang , Wu Zhen , Liu Wen
Published: January 2024

High levels of mitochondrial reactive oxygen species (mROS) are linked to cancer development, which is tightly controlled by the electron transport chain (ETC). However, the epigenetic mechanisms governing ETC gene transcription to drive mROS production and cancer cell growth remain to be fully characterized. Here, we report that protein demethylase PHF8 is overexpressed in many types of cancers, including colon and lung cancer, and is negatively correlated with ETC gene expression. While it is well known to demethylate histones to activate transcription, PHF8 demethylates transcription factor YY1, functioning as a co-repressor for a large set of nuclear-coded ETC genes to drive mROS production and cancer development. In addition to genetically ablating PHF8, pharmacologically targeting PHF8 with a specific chemical inhibitor, iPHF8, is potent in regulating YY1 methylation, ETC gene transcription, mROS production, and cell growth in colon and lung cancer cells. iPHF8 exhibits potency and safety in suppressing tumor growth in cell-line- and patient-derived xenografts in vivo. Our data uncover a key epigenetic mechanism underlying ETC gene transcriptional regulation, demonstrating that targeting the PHF8/YY1 axis has great potential to treat cancers.
Anomalously enhanced ion transport and uptake in functionalized angstrom-scale two-dimensional channels
Authors: Wang Mingzhan , Sadhukhan Tumpa , Lewis Nicholas H. C. , Wang Maoyu , He Xiang , Yan Gangbin , Ying Dongchen , Hoenig Eli , Han Yu , Peng Guiming , Lee One-Sun , Shi Fengyuan , Tiede David M. , Zhou Hua , Tokmakoff Andrei , Schatz George C. , Liu Chong
Published: January 2024

Emulating angstrom-scale dynamics of the highly selective biological ion channels is a challenging task. Recent work on angstrom-scale artificial channels has expanded our understanding of ion transport and uptake mechanisms under confinement. However, the role of chemical environment in such channels is still not well understood. Here, we report the anomalously enhanced transport and uptake of ions under confined MoS
2
-based channels that are ~five angstroms in size. The ion uptake preference in the MoS
2
-based channels can be changed by the selection of surface functional groups and ion uptake sequence due to the interplay between kinetic and thermodynamic factors that depend on whether the ions are mixed or not prior to uptake. Our work offers a holistic picture of ion transport in 2D confinement and highlights ion interplay in this regime.
Cognitive Semantics
Authors: Glebkin Vladimir
Published: January 2024

The book presents two fundamental theories that characterize the cultural-historical perspective in cognitive semantics: the Four-Level Theory of Cognitive Development (FLTCD) and the Sociocultural Theory of Lexical Complexes (STLC) as well as their application to the analysis of specific material. In particular, the book analyzes the sociocultural history of the MACHINE metaphor, specifically its use in the texts of René Descartes and Francis Bacon. The practical embodiment of STLC is demonstrated through the analysis of lexical complexes such as otkryvat' ‘to open,’ kamen' ‘stone,’ and intelligencija ‘intelligentsia.’ In the final chapter of the monograph, FLTCD and STLC are used for the diachronic analysis of semantic change. The monograph will be of interest to a wide range of linguists, psychologists, cultural anthropologists, and philosophers who consider language as a sociocultural phenomenon.
Wave beams, packets and pulses in inhomogeneous non-Hermitian media with dispersive gain or damping
Authors: Poli Emanuele , Bottino Alberto , Korger David , Maj Omar , Palermo Francesco , Weber Hannes
Published: January 2024

Wave beams, packets or pulses are known to be subject to a drift if the properties of the medium change across their extension. This effect is often analyzed considering the dispersive properties of the oscillation, related to the real part of the dispersion relation. The evolution of Gaussian beams/packets/pulses in nonuniform media in the presence of gain or damping is investigated in detail, with particular emphasis on the role of dispersion on both the real and the imaginary part of the dispersion relation. In the paraxial limit, the influence of a non-Hermitian medium on the evolution of the wave can be treated employing the equations derived by Graefe and Schubert in the frame of non-Hermitian quantum mechanics (Phys. Rev. A 83 060101(R)). Analytic solutions of the corresponding paraxial equations are obtained here for a one-dimensional complex dispersion relation characterized by a linear or quadratic dependence on the transverse coordinate (a space coordinate for beams and packets, the time in the co-moving frame for a pulse). In the presence of a constant gradient in both the real and the imaginary part of the dispersion relation, the contribution of the latter can lead to a faster or slower propagation with respect to the Hermitian case, depending on the parameters. In focusing media, a constant gain can counteract dispersive or inhomogeneous damping producing packets of asymptotically constant shape. The analytic formulas derived in this paper offer a way to predict or control the properties of beams/packets/pulses depending on their initial conditions and on the characteristics of the medium.
Predicting the turbulent transport of cosmic rays via neural networks
Authors: Palade D.I.
Published: January 2024

A fast artificial neural network is developed for the prediction of cosmic ray transport
in turbulent astrophysical magnetic fields. The setup is trained and tested on bespoke datasets
that are constructed with the aid of test-particle numerical simulations of relativistic cosmic
ray dynamics in synthetic stochastic fields. The neural network uses, as input, particle and field
properties and estimates transport coefficients 107 faster than standard numerical simulations
with an overall error of ∼5%.
Recent advances in combined Positron Emission Tomography and Magnetic Resonance Imaging
Authors: Galve P. , Rodriguez-Vila B. , Herraiz J.L. , García-Vázquez V. , Malpica N. , Udias J.M. , Torrado-Carvajal A.
Published: January 2024

Hybrid imaging modalities combine two or more medical imaging techniques offering exciting new possibilities to image the structure, function and biochemistry of the human body in far greater detail than has previously been possible to improve patient diagnosis. In this context, simultaneous Positron Emission Tomography and Magnetic Resonance (PET/MR) imaging offers great complementary information, but it also poses challenges from the point of view of hardware and software compatibility. The PET signal may interfere with the MR magnetic field and vice-versa, posing several challenges and constrains in the PET instrumentation for PET/MR systems. Additionally, anatomical maps are needed to properly apply attenuation and scatter corrections to the resulting reconstructed PET images, as well motion estimates to minimize the effects of movement throughout the acquisition. In this review, we summarize the instrumentation implemented in modern PET scanners to overcome these limitations, describing the historical development of hybrid PET/MR scanners. We pay special attention to the methods used in PET to achieve attenuation, scatter and motion correction when it is combined with MR, and how both imaging modalities may be combined in PET image reconstruction algorithms.
Experimental evaluation of the SNR in counting detectors under pile-up conditions
Authors: Magalhaes Debora , Fajardo Pablo , Grybos Pawel , Kleczek Rafal , Kmon Piotr , Otfinowski Piotr , Ruat Marie
Published: January 2024

As a follow-up of a Signal-to-Noise Ratio (SNR) study presented previously, this work
discusses the experimental results obtained for the statistical analysis of photon counting
detector measurements. The test device is a hybrid assembly built with a pixelated 400 μm thick
electron collection Si sensor bump-bonded to a SPHIRD test readout ASIC. The analog front-end in
each pixel of the ASIC produces a pulse of tens of nanoseconds for each X-ray hit, and its digital
circuitry implements both amplitude and time-based pile-up compensation methods, making this
device an excellent candidate for this study. Under pile-up conditions, the SNR of the photon
counting measurements deviates from Poisson statistics and it has been evaluated by applying the
numerical method introduced
in a previous
work. In addition to standard photon counting
operation, two pile-up compensation methods implemented in SPHIRD were tested. The results were
evaluated for individual pixels. The standard photon counting results reproduce the simulated
behavior, presenting a SNR response that peaks around 30% pile-up, and then drops. Meanwhile,
both pile-up compensation methods have presented a comparable effect on improving not only the
count rate but also the statistical response of the system, for the covered count-rate range of up
to 45Mcps/pixel. The obtained results validate the presented methodology to obtain the SNR, also
elucidating the pile-up detrimental effect on the statistical quality of the data.
Imaging and spectrometric performance of SiC Timepix3 radiation camera
Authors: Zaťko B. , Šagátová A. , Hrubčín L. , Kováčová E. , Novák A. , Kurucová N. , Polansky Š. , Jakůbek J.
Published: January 2024

A Schottky barrier radiation detector and pixel imaging sensor fabricated from epitaxially grown SiC semiconductor were analyzed. The detector was based on an 80 μm thick epitaxial SiC layer. Capacitance-voltage measurement was performed to study the thickness of the space charge region of the detector as a function of applied bias. The results showed that the detector was completely depleted at a reverse bias higher than 300 V. The impurity concentration profile was also calculated, which indicated a net impurity concentration below 1.5×1014 cm-3. A prototype of a SiC Timpix3 radiation camera was fabricated, and its energy resolution was investigated using the 241Am radioisotope. The camera exhibited an energy resolution of 4.5 keV for 60 keV gamma photons. X-ray fluorescence photons (from 14 keV to 22 keV) were detected with a resolution below 2.0 keV. The imaging quality of the camera was investigated using a test object. The prototype showed a high-quality image performance with a stable count rate, which was determined from uniform intensity profiles extracted from parts of the test object image. A disadvantage of this prototype is that the radiation hits the detector from the side of the substrate and only then it reaches its active SiC epitaxial layer. This represents a dead layer that reduced the detection efficiency of X-rays below 10 keV.
Preliminary experimental results of tungsten wire calorimeter for CRAFT NNBI
Authors: Yu L. , Xu Y.Z. , Xu Y.J. , Mou X.B. , Chen L.P. , Peng X.F.
Published: January 2024

The comprehensive Research Facility for Fusion Technology(CRAFT) has been carried out since 2019 in China and as an important component of CRAFT, a negative ion-based neutral beam injection sysgem(NNBI) (200–400 keV, 2 MW) is under construction. In order to realize online diagnosis of beam uniformity, a tungsten wire
calorimeter
is developed. The tungsten wire calorimeter is characterized by double-layer tungsten wire mesh structure. During beam bombardment, the tungsten wire mesh is heated and emits light, a visible light camera is used to photograph the tungsten wire calorimeter. The beam profile is obtained by digitizing the light intensity distribution map. In this paper, through the thermal simulation anslysis of tungsten wire,

the installation position of tungsten wire calorimeter are determined and the spatial resolution under different beam divergence are also analyzed.The tungsten wire calorimeter was tested on the beam source test platform, the light intensity distribution maps of the tungsten wire calorimeter under 15 keV–40 keV beam energy were obtained. The work above will accumulate experience for the operation of tungsten wire calorimeter for full scale beam source in the next stage, and provide technical means for the conditioning of negative beam sources.
Tracking a moving point source using triple gamma imaging
Authors: Chmeissani Mokhtar , Kolstein Machiel , Ariño-Estrada Gerard , Macias-Montero José Gabriel , Puigdengoles Carles , García Jorge
Published: January 2024

With positron emission tomography (PET), the positron of a β
+ emitter radioisotope annihilates with a nearby electron
producing a pair of back-to-back 511 keV gamma rays that can be
detected in a scanner surrounding the point source. The position of
the point source is somewhere along the Line of Response (LOR) that
passes through the positions where the 511 keV gammas are detected.
In standard PET, an image reconstruction algorithm is used to
combine these LORs into a final image. This paper presents a new
tomographic imaging technique to locate the position of a β
+
emitting point source without using a standard PET image
reconstruction algorithm. The data were collected with a
Proof-of-Concept (PoC) PET scanner which has high spatial and energy
resolutions. The imaging technique presented in this paper uses
events where a gamma undergoes Compton scattering. The positions
and energies deposited by the Compton scattered gamma define the
surface of a Compton cone (CC) which is the locus of all possible
positions of the point source, allowed by the Compton kinematics.
The position of the same point source is also located somewhere on
the LOR. Therefore, the position of the point source is defined by
the 3 gammas and is given by the intersection point of the LOR and
the Compton cone inside the Field of View (FOV) of the scanner. We
refer to this method as CC×LOR. This new technique can locate
the point source with an uncertainty of about 1 mm, after
collecting a minimum of 200 CC×LOR events.
Performance of a ton-scale water-based liquid scintillator detector
Authors: Zhao Rong , Bignell Lindsey , Jaffe David E. , Rosero Richard , Yeh Minfang , Wang Wei , Zhang Aiwu
Published: January 2024

This study reports the performance and light yield of 1%
concentration water-based liquid scintillator (WbLS) deployed in a
1000-liter detector. A light yield of 99± 15 photons per MeV is
determined by comparing data with simulation. This result aligns
with our previous light yield determination using smaller detectors,
thus establishing a solid foundation for the ongoing development and
deployment of WbLS in larger-scale detectors. The feasibility of
in situ preparation and the stability of light yield in WbLS
are demonstrated, reinforcing its suitability for long-term
experimental endeavors.
Data analysis methods and applications of the eddy current diagnostic system in the Keda Torus eXperiment device
Authors: Chen Zheng , Tao Zhen , Yolbarsop Adil , Li Hong , Zhang Yuan , Yan Wentan , Rao Xianhao , Ren Shunrong , Tian Furen , Mao Wenzhe , Wei Zian , Liu Zixi , Zhou Chu , Liu Adi , Lan Tao , Xie Jinlin , Zhou Haiyang , Wen Xiaohui , Wang Hai , Zhuang Ge , Xiao Chijin , Ding Weixing , Liu Wandong
Published: January 2024

Since the establishment of the eddy current diagnostic
system within the Keda Torus eXperiment (KTX) device, it has
unveiled many applications. Recent developments have introduced
innovative data analysis techniques alongside compelling
experimental results, underscoring the necessity for a comprehensive
summary of the system's data analysis approaches and broad
applications. Notable features of the system encompass exceptional
precision, the ability to encompass shell currents on the entirety
of the closed boundary, vector detection of shell currents, and
measurement of diverse physical quantities. In terms of data
analysis methodologies, meticulous scrutiny of the null field region
is conducted, and we reveal a distinctive characteristic within the
complex shell current signals, namely the asymmetry of the
amplitudes of ±n Fourier coefficients. Moreover, the Hodge
decomposition emerges as a pivotal technique, allowing for the
distinctive separation of shell currents into three orthogonal
components based on their distinct spatial topological
properties. With regard to practical applications, an in-depth
examination of the vector potential and magnetic helicity flux
densities are presented in detail, further highlighting the
far-reaching utility of the system's capabilities.
Full-flow surface defect identification method based on spot scanning scattering for unpatterned wafer
Authors: Qu Dingjun , Zhou Zuoda , Li Zhiwei , Ding Ruizhe , Jin Wei , Ru Yu , Luo Haiyan , Xiong Wei
Published: January 2024

As the critical dimensions of semiconductor manufacturing
processes gradually decrease, the requirements for production yield
management become increasingly stringent. During the manufacturing
process, there are many different types of defects, such as
micron-sized particles, millimeter-sized scratches, etc. Multiple
categories and different scales bring great challenges to the
detection and identification of defects. This paper provides a
full-flow surface defect identification method based on spot
scanning scattering for unpatterned wafers. First, an adaptive
threshold method with dynamic kernel windows is used to perform
line-by-line scanning inspection of the wafer Mercator image. The
3σ decision strategy is used to avoid the impact of defects
on background estimation and to improve detection sensitivity. After
morphological processing, connected domain analysis is performed to
obtain the defect mask, and feature information such as the shape,
size, and distribution of the defect is extracted. Finally, the
defect identification is performed by rules based binning, and the
identified defects are converted into wafer polar coordinate image
for display and analysis. In the experiments, the proposed method is
used to identify micron-scale particles as well as large scratches
on the millimeter scale for SiC wafers. Relative to the actual
production rate requirement of 20 wafers per hour, the analysis time
for a 6-inch wafer is 24.4 s, which can meet the
requirement. Meanwhile, the test results illustrate the
effectiveness of the method. The proposed method is recommended for
early-stage defect detection and identification of unpatterned
wafers.
Winter post-droughts amplify extreme nitrate concentrations in German rivers
Authors: Saavedra Felipe , Musolff Andreas , Von Freyberg Jana , Merz Ralf , Knöller Kay , Müller Christin , Brunner Manuela , Tarasova Larisa
Published: January 2024

Hydrological extremes can affect nutrient export from catchments to streams, posing a threat to aquatic ecosystems. In this study, we investigated the effects of hydrological drought on nitrate concentrations in the streamflow of 182 German catchments from 1980 to 2020. We found that across all seasons, 40% and 25% of the catchments showed significantly lower nitrate concentrations during drought and post-droughts, respectively, when compared to non-drought conditions. However, we observed pronounced spatial variability in the responses, particularly during winter droughts and post-droughts, with more catchments exhibiting higher nitrate concentrations. Specifically, nitrate concentrations were significantly higher in 25% of the study catchments during winter droughts, particularly in wetter catchments with low nitrogen retention. During winter post-droughts, nitrate concentrations are significantly higher in 19% of the catchments, especially in wetter catchments with more nitrogen surplus. Moreover, the likelihood of nitrate seasonal extremes increased by 6% during winter post-drought in our study catchments. Considering the projected increase in the frequency of droughts in Germany, the increase in nitrate concentrations during the corresponding post-drought periods poses a potential threat to aquatic ecosystem health.
Reducing global food loss and waste could improve air quality and lower the risk of premature mortality
Authors: Gatto Alessandro , Chepeliev Maksym
Published: January 2024

While the global food system substantially contributes to environmental degradation and climate change, significant amounts of lost or wasted foods along the food supply chain actively contribute to global air pollution and related health risks. In this study, we use an environmentally-extended input–output model to quantify air pollution embedded in global food loss and waste (FLW) and investigate how FLW reduction policies can mitigate air pollution linked to food consumption, decreasing associated premature mortality risks across global regions. While estimating a positive impact of FLW reduction policies on decreasing air pollution levels (from −1.5% of SO2 emissions to −10.2% of NH3 emissions) and mortality reductions (over 67 000 lives worldwide) our findings highlight that rebound effects, wherein a reallocation of consumption from food to non-food commodities, decrease health and environmental benefits by over three quarters (compared to the case with no rebound). Such rebound effects can be substantially mitigated when final consumption shifts towards less pollution-intensive products, such as service activities, rather than conforming to the current composition of non-food consumption. Our results suggest that FLW-related policies would benefit from complementary measures that incentivize sustainable non-food consumption to effectively foster the transition towards a healthier and more sustainable planet.
Lattice aggregations of boxes and symmetric functions
Authors: Rozhkovskaya Natasha
Published: January 2024

We introduce two lattice growth models: aggregation of l-dimensional boxes and aggregation of partitions with l parts. We describe properties of the models: the parameter set of aggregations, the moments of the random variable of the number of growth directions, asymptotical behavior of proportions of the most frequent transitions of two- and three-dimensional self-aggregations.
Possible impact of North Atlantic sea surface temperature on decadal variability of dust activity in Gobi Desert
Authors: Park Yeonsu , Kim Si-Wan , Yang Young-Min , Kim Kyoung-Min , Sung Mi-Kyung , An Soon-Il
Published: January 2024

Semiarid to arid regions located in north of China are known as one of the largest sources of dust aerosols in the globe. Previous studies demonstrated direct and indirect effects of atmospheric dust loading on climate. The surface and meteorological properties are known to be affecting dust entrainment process. In this study, we found decadal variations of dust occurrence in Gobi Desert with the period of ∼24 years, utilizing the data acquired at the surface meteorological stations. An analysis of reanalysis datasets shows significant correlations between February North Atlantic Sea Surface Temperature (NASST) and precipitation in Gobi Desert and Mongolia in the following summer, causing a decadal variation of dust event frequency in the subsequent spring over the region. Strong time-lagged correlation is shown to be linked to an atmospheric wave train pattern that initiated from the NASST region, affecting large-scale circulation, ultimately causing surface drought over Gobi Desert.
Flexible UV detectors based on in-situ hydrogen doped amorphous Ga2O3 with high photo-to-dark current ratio
Authors: Sui Yanxin , Liang Huili , Huo Wenxing , Zhan Xiaozhi , Zhu Tao , Mei Zengxia
Published: January 2024

Amorphous Ga2O3 (a-Ga2O3) has been attracting more and more attention due to its unique merits such as wide bandgap (∼4.9 eV), low growth temperature, large-scale uniformity, low cost and energy efficient, making it a powerful competitor in flexible deep ultraviolet (UV) photodetection. Although the responsivity of the ever-reported a-Ga2O3 UV photodetectors (PDs) is usually in the level of hundreds of A/W, it is often accompanied by a large dark current due to the presence of abundant oxygen vacancy (V
O) defects, which severely limits the possibility to detect weak signals and achieve versatile applications. In this work, the V
O defects in a-Ga2O3 thin films are successfully passivated by in-situ hydrogen doping during the magnetron sputtering process. As a result, the dark current of a-Ga2O3 UV PD is remarkably suppressed to 5.17 × 10−11 A at a bias of 5 V. Importantly, the photocurrent of the corresponding device is still as high as 1.37 × 10−3 A, leading to a high photo-to-dark current ratio of 2.65 × 107 and the capability to detect the UV light with the intensity below 10 nW cm−2. Moreover, the H-doped a-Ga2O3 thin films have also been deposited on polyethylene naphtholate substrates to construct flexible UV PDs, which exhibit no great degradation in bending states and fatigue tests. These results demonstrate that hydrogen doping can effectively improve the performance of a-Ga2O3 UV PDs, further promoting its practical application in various areas.