bluuebunny/crossref_metadata_2025 huggingface dataset:
Visualizing correlation between carrier mobility and defect density in MoS2 FET
Authors: Chen Fu-Xiang Rikudo , Kawakami Naoya , Lee Chang-Tsan , Shih Pen-Yuan , Wu Zi-Cheng , Yang Yong-Cheng , Tu Hao-Wei , Jian Wen-Bin , Hu Chenming , Lin Chun-Liang
Published: October 2022

Transition metal dichalcogenides (TMDs) with only a few atoms thickness provide an excellent solution to scale down current semiconductor devices. Many studies have demonstrated that molybdenum disulfide (MoS2), a member of TMDs, is promising as a channel material to fabricate field-effect transistors (FETs). However, the carrier mobility in MoS2 FET is always far lower than the theoretical prediction. Although this poor performance can be attributed to the defects, it still lacks a quantitative analysis clarifying the correlation between carrier mobility and defect density. In this work, by using scanning tunneling microscopy, we directly counted the defects in MoS2 FETs with different carrier mobility. We found that vacancies and impurities equally contribute to carrier mobility and the total defect density induces a power-law decreasing tendency to the carrier mobility of MoS2 FET. Our current results directly prove that the reduction of point defects can exponentially improve the carrier mobility of FETs made by TMDs.
Stability of thermally bistable states and their switching in superconducting weak link
Authors: Biswas Sourav , Wahi Pankaj , Kumar Gupta Anjan
Published: October 2022

Superconducting weak link (WL), acting as a Josephson junction (JJ), is one of the widely used elements in superconductor science and quantum circuits. A hysteretic JJ with robust switching between its superconducting and resistive state is an excellent candidate for single-photon detection. However, the ubiquitous fluctuations in the junction strongly influence the stability of the states and, thus, the transition from one to the other. Here, we present an experimental study of switching statistics of critical and retrapping currents of a JJ based on niobium WL in its hysteretic regime. The mean lifetimes of the two metastable states, namely, the zero-voltage superconducting state and finite-voltage resistive state, are estimated from the distributions. Further, close to the hysteresis crossover temperature, observed telegraphic noise in the time domain due to random switching between the states provides their lifetimes directly. We present a thermal model introducing a double-well (bistable) feature with an intriguing quantity with respect to the devices’ temperature states. The effects of temperature fluctuations on the stability of the states are shown. We discuss our results toward further improvement of the efficiency of superconducting WL or nanowire single-photon detectors.
Dynamical geography and transition paths of Sargassum in the tropical Atlantic
Authors: Beron-Vera F. J. , Olascoaga M. J. , Putman N. F. , Triñanes J. , Goni G. J. , Lumpkin R.
Published: October 2022

By analyzing a time-homogeneous Markov chain constructed using trajectories of undrogued drifting buoys from the NOAA Global Drifter Program, we find that probability density can distribute in a manner that resembles very closely the recently observed recurrent belt of high Sargassum concentration in the tropical Atlantic between 5 and 10°N, coined the Great Atlantic Sargassum Belt (GASB). A spectral analysis of the associated transition matrix further unveils a forward attracting almost-invariant set in the northwestern Gulf of Mexico with a corresponding basin of attraction weakly connected with the Sargasso Sea but including the nutrient-rich regions around the Amazon and Orinoco rivers mouths and also the upwelling system off the northern coast of West Africa. This represents a data-based inference of potential remote sources of Sargassum recurrently invading the Intra-Americas Seas (IAS). By further applying Transition Path Theory (TPT) to the data-derived Markov chain model, two potential pathways for Sargassum into the IAS from the upwelling system off the coast of Africa are revealed. One TPT-inferred pathway takes place along the GASB. The second pathway is more southern and slower, first going through the Gulf of Guinea, then across the tropical Atlantic toward the mouth of the Amazon River, and finally along the northeastern South American margin. The existence of such a southern TPT-inferred pathway may have consequences for bloom stimulation by nutrients from river runoff.
Effect of surface modifier and solvent on the affinity between the surface-modified solid and organic solvent: A molecular dynamics study
Authors: Saito Takamasa , Takebayashi Ryo , Kubo Masaki , Tsukada Takao , Shoji Eita , Kikugawa Gota , Surblys Donatas
Published: October 2022

To control the dispersibility of surface-modified nanoparticles in fluid, it is important to evaluate the affinity between surface-modified nanoparticles and solvents and elucidate the effect of surface modification on the affinity at the molecular level. In this study, the effect of the chain length of the surface modifier and solvent on the work of adhesion Wadh was investigated for the carboxylic acid-modified Al2O3/n-alkane interface by molecular dynamics simulations using the phantom-wall method. Here, we adopted hexanoic acid, decanoic acid, and octadecanoic acid as the surface modifiers and n-hexane, n-decane, and n-dodecane as the solvents. At a surface coverage of 100%, the effect of the modifier length on Wadh was small because the solvent did not penetrate any modifier layers with a dense packing state. At a surface coverage of 50%, the solvent penetration was good except for the octadecanoic acid modifier, and Wadh for the decanoic acid modifier was higher than that for the hexanoic acid and octadecanoic acid modifiers. For the decanoic acid modifier with a surface coverage of 50%, the effect of the solvent length on Wadh was small because the density distributions of the modifier and solvent near the interface were almost the same in all solvent systems. Solvent penetration was evaluated using the overlap parameter, which is the degree of overlap of the density distribution. A large penetration resulted in high Wadh. We demonstrated that the affinity between surface-modified nanoparticles and solvents can be increased by ensuring high modifier-solvent penetration via adjusting the surface coverage and surface modifier.
Equation of state of solid parahydrogen using ab initio two-body and three-body interaction potentials
Authors: Ibrahim Alexander , Roy Pierre-Nicholas
Published: October 2022

We present the equation of state of solid parahydrogen between 0.024 and 0.1 Å−3 at T = 4.2 K, calculated using path integral Monte Carlo simulations, with ab initio two-body and three-body interaction potentials. We correct for finite size simulation errors using potential tail corrections. Trotter factorization errors are accounted for either via extrapolation or by using a suitably small imaginary time step. We incorporate the three-body interaction using two methods: (1) the full inclusion method, where pair and three-body interactions are used in both Monte Carlo sampling and in the energy estimators, and (2) the perturbative method, where three-body interactions are omitted from sampling but are still present in energy estimations. Both treatments of the three-body interaction return very similar total energies and pressures. The presence of three-body interactions has only minor effects on the structural properties of the solid. Whereas the pair interaction, on its own, significantly overestimates the pressure of solid parahydrogen, the additional presence of the three-body interaction causes a severe underestimation of the pressure. Our findings suggest that accurate simulations of solid parahydrogen require four-body and possibly higher-order many-body interactions. It may also be the case that static interaction potentials are entirely unsuitable for simulations of solid parahydrogen at high densities.
Transfer of phase coherence by the dipolar field in total correlation liquid state nuclear magnetic resonance spectroscopy
Authors: Pelupessy Philippe
Published: October 2022

In this work, it is shown that radio-frequency pulse trains designed for total correlation nuclear magnetic resonance spectroscopy can mediate inter-molecular transfer of phase coherence from one spin species to another by the dipolar field. In contrast to previous studies (where short pulses interleaved with long free precession delays were used), here the transverse component of the dipolar field plays an important role. The transfer is so efficient that signal intensities close to those of a single pulse experiment can be achieved. The results are rationalized by numerical simulations that take into account relaxation and diffusion.
Many recent density functionals are numerically ill-behaved
Authors: Lehtola Susi , Marques Miguel A. L.
Published: October 2022

Most computational studies in chemistry and materials science are based on the use of density functional theory. Although the exact density functional is unknown, several density functional approximations (DFAs) offer a good balance of affordable computational cost and semi-quantitative accuracy for applications. The development of DFAs still continues on many fronts, and several new DFAs aiming for improved accuracy are published every year. However, the numerical behavior of these DFAs is an often-overlooked problem. In this work, we look at all 592 DFAs for three-dimensional systems available in Libxc 5.2.2 and examine the convergence of the density functional total energy based on tabulated atomic Hartree–Fock wave functions. We show that several recent DFAs, including the celebrated SCAN family of functionals, show impractically slow convergence with typically used numerical quadrature schemes, making these functionals unsuitable both for routine applications and high-precision studies, as thousands of radial quadrature points may be required to achieve sub-μEh accurate total energies for these functionals, while standard quadrature grids like the SG-3 grid only contain O(100) radial quadrature points. These results are both a warning to users to always check the sufficiency of the quadrature grid when adopting novel functionals, as well as a guideline to the theory community to develop better-behaved density functionals.
Weight gain and enteric methane production of cattle fed on tropical grasses
Authors: Korir D. , Marquardt S. , Eckard R. , Sanchez A. , Dickhoefer U. , Merbold L. , Butterbach-Bahl K. , Jones C. , Robertson-Dean M. , Goopy J.
Published: October 2022

Context Planted grasses are becoming an increasingly important feed resource for tropical smallholder ruminant production; yet, limited research has been conducted to quantify productivity or enteric methane (CH4) production of animals consuming these grasses. Aim An experiment was conducted to assess yields and nutritional attributes of the following three tropical grasses: Cenchrus purpureus var. Kakamega 1 (Napier), Chloris gayana var. Boma (Rhodes) and Urochloa brizantha var. Xaeres (Brachiaria), and quantify enteric CH4 production of cattle fed on them. Methods Yearling Boran steers (n:18; initial liveweight 216 ± 5.8 kg (mean ± s.e.m.) were allocated to one of three grasses, in a completely randomised design and fed ad libitum for two feeding periods, each period lasting for 70 days. Intake, liveweight (LW), apparent total-tract digestibility and enteric CH4 production were assessed. The grasses used were grown on site and biomass yields were monitored over a 2-year period. Animal growth was also simulated to a final weight of 350 kg, and the amount of feed and size of land required to produce, and days to reach final weight, were estimated. Key results Mean voluntary dry-matter intake (DMI) and ADG were higher (P < 0.05) in Period 2 than in Period 1, but did not differ among treatments (P > 0.05) within period. Methane yield (MY; CH4 g/DMI kg) was similar among treatments (26.7–28.5, P = 0.26) but Napier had a higher CH4 conversion factor [Ym; CH4 (MJ)/gross energy intake (MJ)] than did Rhodes and Brachiaria (0.0987 vs 0.0873 and 0.0903 respectively; P = 0.013). Our modelling indicated that steers consuming Rhodes took at least 30 more days to reach the target LW, required larger land area for feed production and produced more enteric CH4 than did the other two diets. Conclusion Even though animal performance and MY among treatments did not differ, the animals had higher MY and Ym than currently estimated by the Intergovernmental Panel on Climate Change. Implication The three grasses supported similar animal growth rate, implying that growing of higher-yielding grasses such as Napier offers an opportunity to optimise land productivity in the tropics. However, suitable feeding practices such as protein supplementation need to be explored to enhance ruminant production and reduce enteric CH4 production.
Human- and lightning-caused wildland fire ignition clusters in British Columbia, Canada
Authors: Coogan Sean C. P. , Aftergood Olivia , Flannigan Mike D.
Published: October 2022

Wildland fire is a common occurrence in western Canada, with record-setting area burned recorded in British Columbia (BC) in the past decade. Here, we used the unsupervised machine learning algorithm HDBSCAN to identify high-density clusters of both human- and lightning-caused wildfire ignitions in BC using data from 2006 to 2020. We found that human-caused ignition clusters tended to occur around population centres, First Nations communities, roads and valleys, and were more common in the southern half of the province, which is more populated. Lightning-ignition clusters were generally fewer in number and larger in size than human-caused fires for most hyperparameter settings. There were significant differences (X2 = 1884.8, d.f. = 7, P-value <2.2 × 10−16) in fuels associated with lightning- versus human-caused ignition clusters, with human-ignition cluster fires being more often found within leafless aspen (D1) and ponderosas pine and Douglas fir (C7) fuel types. These high-density clusters highlight regions where the greatest densities of both lightning- and human-caused fires have occurred in the province, thereby identifying regions of potential interest to wildland fire managers, researchers and various communities and industries.
Pandemic origins and a One Health approach to preparedness and prevention: Solutions based on SARS-CoV-2 and other RNA viruses
Authors: Keusch Gerald T. , Amuasi John H. , Anderson Danielle E. , Daszak Peter , Eckerle Isabella , Field Hume , Koopmans Marion , Lam Sai Kit , Das Neves Carlos G. , Peiris Malik , Perlman Stanley , Wacharapluesadee Supaporn , Yadana Su , Saif Linda
Published: October 2022

COVID-19 is the latest zoonotic RNA virus epidemic of concern. Learning how it began and spread will help to determine how to reduce the risk of future events. We review major RNA virus outbreaks since 1967 to identify common features and opportunities to prevent emergence, including ancestral viral origins in birds, bats, and other mammals; animal reservoirs and intermediate hosts; and pathways for zoonotic spillover and community spread, leading to local, regional, or international outbreaks. The increasing scientific evidence concerning the origins of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is most consistent with a zoonotic origin and a spillover pathway from wildlife to people via wildlife farming and the wildlife trade. We apply what we know about these outbreaks to identify relevant, feasible, and implementable interventions. We identify three primary targets for pandemic prevention and preparedness: first, smart surveillance coupled with epidemiological risk assessment across wildlife–livestock–human (One Health) spillover interfaces; second, research to enhance pandemic preparedness and expedite development of vaccines and therapeutics; and third, strategies to reduce underlying drivers of spillover risk and spread and reduce the influence of misinformation. For all three, continued efforts to improve and integrate biosafety and biosecurity with the implementation of a One Health approach are essential. We discuss new models to address the challenges of creating an inclusive and effective governance structure, with the necessary stable funding for cross-disciplinary collaborative research. Finally, we offer recommendations for feasible actions to close the knowledge gaps across the One Health continuum and improve preparedness and response in the future.
Decomposing predictability to identify dominant causal drivers in complex ecosystems
Authors: Suzuki Kenta , Matsuzaki Shin-ichiro S. , Masuya Hiroshi
Published: October 2022

Ecosystems are complex systems of various physical, biological, and chemical processes. Since ecosystem dynamics are composed of a mixture of different levels of stochasticity and nonlinearity, handling these data is a challenge for existing methods of time series–based causal inferences. Here, we show that, by harnessing contemporary machine learning approaches, the concept of Granger causality can be effectively extended to the analysis of complex ecosystem time series and bridge the gap between dynamical and statistical approaches. The central idea is to use an ensemble of fast and highly predictive artificial neural networks to select a minimal set of variables that maximizes the prediction of a given variable. It enables decomposition of the relationship among variables through quantifying the contribution of an individual variable to the overall predictive performance. We show how our approach, EcohNet, can improve interaction network inference for a mesocosm experiment and simulated ecosystems. The application of the method to a long-term lake monitoring dataset yielded interpretable results on the drivers causing cyanobacteria blooms, which is a serious threat to ecological integrity and ecosystem services. Since performance of EcohNet is enhanced by its predictive capabilities, it also provides an optimized forecasting of overall components in ecosystems. EcohNet could be used to analyze complex and hybrid multivariate time series in many scientific areas not limited to ecosystems.
Morphological similarity of amygdala-ventral prefrontal pathways represents trait anxiety in younger and older adults
Authors: Kim Wonyoung , Kim M. Justin
Published: October 2022

Stronger amygdala-ventral prefrontal white matter connectivity has been associated with lower trait anxiety, possibly reflecting an increased capacity for efficient communication between the two regions. However, there are also reports arguing against this brain–anxiety association. To address these inconsistencies in the literature, we tested the possibility that idiosyncratic tract morphology may account for meaningful individual differences in trait anxiety, even among those with comparable microstructural integrity. Here, we adopted intersubject representational similarity analysis, an analytic framework that captures multivariate patterns of similarity, to analyze the morphological similarity of amygdala-ventral prefrontal pathways. Data drawn from the Leipzig Study for Mind–Body-Emotion Interactions dataset showed that younger adults (20 to 35 y of age) with low trait anxiety, in contrast to trait-anxious individuals, had consistently similar morphological configurations in their left amygdala-ventral prefrontal pathways. Additional tests on an independent sample of older adults (60 to 75 y of age) validated this finding. Our study reveals a generalizable pattern of brain–anxiety association that is embedded within the shared geometries between fiber tract morphology and trait anxiety data.
Visualizing the interplay of Dirac mass gap and magnetism at nanoscale in intrinsic magnetic topological insulators
Authors: Liu Mengke , Lei Chao , Kim Hyunsue , Li Yanxing , Frammolino Lisa , Yan Jiaqiang , Macdonald Allan H. , Shih Chih-Kang
Published: October 2022

In intrinsic magnetic topological insulators, Dirac surface-state gaps are prerequisites for quantum anomalous Hall and axion insulating states. Unambiguous experimental identification of these gaps has proved to be a challenge, however. Here, we use molecular beam epitaxy to grow intrinsic MnBi
2
Te
4
thin films. Using scanning tunneling microscopy/spectroscopy, we directly visualize the Dirac mass gap and its disappearance below and above the magnetic order temperature. We further reveal the interplay of Dirac mass gaps and local magnetic defects. We find that, in high defect regions, the Dirac mass gap collapses.
Ab initio
and coupled Dirac cone model calculations provide insight into the microscopic origin of the correlation between defect density and spatial gap variations. This work provides unambiguous identification of the Dirac mass gap in MnBi
2
Te
4
and, by revealing the microscopic origin of its gap variation, establishes a material design principle for realizing exotic states in intrinsic magnetic topological insulators.
Quantum oscillations in the magnetization and density of states of insulators
Authors: Panda Animesh , Banerjee Sumilan , Randeria Mohit
Published: October 2022

The observation of

1
/
B

-periodic behavior in Kondo insulators and semiconductor quantum wells challenges the conventional wisdom that quantum oscillations (QOs) necessarily arise from Fermi surfaces in metals. We revisit recently proposed theories for this phenomenon, focusing on a minimal model of an insulator with a hybridization gap between two opposite-parity light and heavy mass bands with an inverted band structure. We show that there are characteristic differences between the QO frequencies in the magnetization and the low-energy density of states (LE-DOS) of these insulators, in marked contrast to metals where all observables exhibit oscillations at the same frequency. The magnetization oscillations arising from occupied Landau levels occur at the same frequency that would exist in the unhybridized case. The LE-DOS oscillations in a disorder-free system are dominated by gap-edge states and exhibit a beat pattern between two distinct frequencies at low temperature. Disorder-induced in-gap states lead to an additional contribution to the DOS at the unhybridized frequency. The temperature dependence of the amplitude and phase of the magnetization and DOS oscillations are also qualitatively different and show marked deviations from the Lifshitz–Kosevich form well known in metals. We also compute transport to ensure that we are probing a regime with insulating upturns in the direct current (DC) resistivity.
Direct observation of stepping rotation of V-ATPase reveals rigid component in coupling between V
o
and V
1
motors
Authors: Otomo Akihiro , Iida Tatsuya , Okuni Yasuko , Ueno Hiroshi , Murata Takeshi , Iino Ryota
Published: October 2022

V-ATPases are rotary motor proteins that convert the chemical energy of ATP into the electrochemical potential of ions across cell membranes. V-ATPases consist of two rotary motors, V
o
and V
1
, and
Enterococcus hirae
V-ATPase (EhV
o
V
1
) actively transports Na
+
in V
o
(EhV
o
) by using torque generated by ATP hydrolysis in V
1
(EhV
1
). Here, we observed ATP-driven stepping rotation of detergent-solubilized EhV
o
V
1
wild-type, aE634A, and BR350K mutants under various Na
+
and ATP concentrations ([Na
+
] and [ATP], respectively) by using a 40-nm gold nanoparticle as a low-load probe. When [Na
+
] was low and [ATP] was high, under the condition that only Na
+
binding to EhV
o
is rate limiting, wild-type and aE634A exhibited 10 pausing positions reflecting 10-fold symmetry of the EhV
o
rotor and almost no backward steps. Duration time before the forward steps was inversely proportional to [Na
+
], confirming that Na
+
binding triggers the steps. When both [ATP] and [Na
+
] were low, under the condition that both Na
+
and ATP bindings are rate limiting, aE634A exhibited 13 pausing positions reflecting 10- and 3-fold symmetries of EhV
o
and EhV
1
, respectively. The distribution of duration time before the forward step was fitted well by the sum of two exponential decay functions with distinct time constants. Furthermore, occasional backward steps smaller than 36° were observed. Small backward steps were also observed during three long ATP cleavage pauses of BR350K. These results indicate that EhV
o
and EhV
1
do not share pausing positions, Na
+
and ATP bindings occur at different angles, and the coupling between EhV
o
and EhV
1
has a rigid component.
Epigenetic factor competition reshapes the EMT landscape
Authors: Al-Radhawi M. Ali , Tripathi Shubham , Zhang Yun , Sontag Eduardo D. , Levine Herbert
Published: October 2022

The emergence of and transitions between distinct phenotypes in isogenic cells can be attributed to the intricate interplay of epigenetic marks, external signals, and gene-regulatory elements. These elements include chromatin remodelers, histone modifiers, transcription factors, and regulatory RNAs. Mathematical models known as gene-regulatory networks (GRNs) are an increasingly important tool to unravel the workings of such complex networks. In such models, epigenetic factors are usually proposed to act on the chromatin regions directly involved in the expression of relevant genes. However, it has been well-established that these factors operate globally and compete with each other for targets genome-wide. Therefore, a perturbation of the activity of a regulator can redistribute epigenetic marks across the genome and modulate the levels of competing regulators. In this paper, we propose a conceptual and mathematical modeling framework that incorporates both local and global competition effects between antagonistic epigenetic regulators, in addition to local transcription factors, and show the counterintuitive consequences of such interactions. We apply our approach to recent experimental findings on the epithelial–mesenchymal transition (EMT). We show that it can explain the puzzling experimental data, as well as provide verifiable predictions.
US voter rights in translation
Authors: Riemland Matt
Published: October 2022

Felons’ voting rights have featured prominently in debates over voter suppression in theUnited States, particularly in Florida, where a 2018 state constitutional amendment reinstated voting rights to the state’s 1.4 million former felons (Robles 2018). Florida also has a high concentration of Spanish-speaking voters with Limited English Proficiency (LEP), making Spanish-language voting information crucial. Inadequate translations of voter information may misrepresent voter eligibility for LEP Spanish-speaking former felons in Florida. Using a parallel corpus, this article’s central research question investigates how semantic shifts occur in Spanish translations of “felony” and “felon” in online voter information for seven Florida counties. The results reveal a number of misrepresentative semantic shifts in both human- and machine-translated Spanish voter information. Such shifts may impinge on individuals’ constitutional rights.
Forest school
Authors: Harris Frances
Published: October 2022

This review aims to summarise existing research on the forest-based pedagogical approach known as forest school, as developed in the UK. Modelled on the nature kindergartens of northern Europe, forest school is popular in the UK and is now being practiced or explored in other countries around the world. Drawing on papers specifically researching forest school, identified through the Scopus database, it identifies and reviews key themes emerging from the literature: research on its development, relationship to classroom teaching and the national curriculum, impact on children’s development, and their relationship to the environment and environmental behaviour. It identifies the challenges and tensions emerging in the practice of forest school, between the performative agenda of schools and the alternative learning approaches embedded in forest school praxis. It summarises the attempts by several authors to develop theoretical models of forest school. It discusses the transferability of this forest education practice to new cultures, environments and educational systems. Finally, it concludes by identifying challenges for further research.
Impact of non-fullerene acceptors and solvent additive on the nanomorphology, device performance, and photostability of PTB7-Th polymer based organic solar cells
Authors: Khan Javed Alam , Sharma Ramakant , Panwar Ajay Singh , Gupta Dipti
Published: October 2022

Non-fullerene acceptors have recently ignited extensive interest in organic solar cells (OSCs) because of their higher power conversion efficiency (PCE) than their fullerene counterparts. Though the effect of solvent additive 1, 8-diiodooctane (DIO) has been studied extensively for fullerene-based acceptor OSCs, not much is known for non-fullerene acceptors OSCs. In our work, bulk-heterojunction (BHJ) OSCs were fabricated by blending fullerene (PC71BM) and non-fullerene (ITIC and IEICO-4F) acceptors with low bandgap polymer donor (PTB7-Th). Further, the effects of non-fullerene acceptors on the nanomorphology, performance, and photostability of the devices were investigated. In the absence of DIO, devices with IEICO-4F acceptor showed higher PCE than PTB7-Th: ITIC and PTB7-Th: PC71BM BHJ-OSCs due to their absorption in near infrared along with high J
sc. The addition of DIO increased PCE in PTB7-Th: PC71BM BHJ-OSCs due to improved miscibility of fullerene molecules, higher donor/acceptor interface area, and improved phase separation. However, DIO adversely affected the overall device performance in PTB7-Th: IEICO-4F and PTB7-Th: ITIC BHJ-OSCs. Furthermore, devices processed with DIO were less photostable and exhibited faster degradation due to the photoacid effect of the DIO additive.
Antibacterial effects of in situ zinc oxide nanoparticles generated inside the poly (acrylamide-co-hydroxyethylmethacrylate) nanocomposite
Authors: Pereyra J Y Del C , Barbero C A , Acevedo D F , Yslas E I
Published: October 2022

The present work reports the antibacterial activity against Pseudomonas
aeruginosa of a nanocomposite made of zinc oxide nanoparticles dispersed in a poly(acrylamide-co-hydroxyethylmethacrylate) matrix (PAAm-Hema-ZnONPs). The in situ synthesis of ZnONPs inside of the PAAm-Hema crosslinked network is described. Moreover, the physicochemical properties of the PAAm-Hema-ZnONPs nanocomposite are analyzed. The results confirm that the PAAm-Hema hydrogel provides an excellent scaffold to generate ZnONPs. The presence of ZnONPs inside the hydrogel was confirmed by UV–visible (band at 320 nm), by Infrared spectroscopy (peak at 470 cm−1), SEM, and TEM images. The presence of NPs in PAAm-Hema diminish the swelling percentage by 70%, and the Young modulus by 33.7%, compared with pristine hydrogel. The 75% of ZnONPs are released from the nanocomposite after 48 h of spontaneous diffusion, allowing the use of the nanocomposite as an antibacterial agent. In vitro, the agar diffusion test presents an inhibition halo against P. aeruginosa bacteria 50% higher than the unloaded hydrogel. Also, the PAAm-Hema-ZnONPs live/dead test shows 54% of dead cells more than the hydrogel. These results suggest that the easy, one-step way generated composites can be used in biomedical applications as antimicrobial agents.
Online triggers for supernova and pre-supernova neutrino detection with cryogenic detectors
Authors: Eller P. , Ferreiro Iachellini N. , Pattavina L. , Shtembari L.
Published: October 2022

Supernovae (SNe) are among the most energetic events in the universe still far from being fully understood. An early and prompt detection of neutrinos is a one-time opportunity for the realization of the first multi-messenger observation of these events. In this work, we present the prospects of detecting neutrinos produced before (pre-SN) and during a SN while running an advanced cryogenic detector. Recent advances in the cryogenic detector technique and the discovery of coherent elastic neutrino-nucleus scattering offer a wealth of opportunities in neutrino detection. The combination of the excellent energy resolution of this experimental technique, with the high cross section of this detection channel and its equal sensitivity to all neutrino flavors, enables the realization of highly sensitive neutrino telescopes of the size of a few tens of cm, as the newly proposed RES-NOVA experiment. We present a detailed study on the detection promptness of pre-SN and SN neutrino signals, with direct comparisons among different classes of test statistics. While the well-established Poisson test offers in general best performance under optimal conditions, the nonparametric Recursive Product of Spacing statistical test (RPS) is more robust for triggering astrophysical neutrino signals with no specific prior knowledge. Based on our statistical tests the RES-NOVA experiment is able to identify SN neutrino signals at a 15 kpc distance with 95% of success rate, and pre-SN signal as far as 450 pc with a pre-warn time of the order of 10 s. These results demonstrate the potential of RPS for the identification of neutrino signals and the physics reach of the RES-NOVA experiment.
Cosmology from the kinetic polarized Sunyaev Zel'dovich effect
Authors: Hotinli Selim C. , Holder Gilbert P. , Johnson Matthew C. , Kamionkowski Marc
Published: October 2022

The cosmic microwave background (CMB) photons that scatter off free electrons in the large-scale structure induce a linear polarization pattern proportional to the remote CMB temperature quadrupole observed in the electrons' rest frame. The associated blackbody polarization anisotropies are known as the polarized Sunyaev Zel'dovich (pSZ) effect. Relativistic corrections to the remote quadrupole field give rise to a non-blackbody polarization anisotropy proportional to the square of the transverse peculiar velocity field; this is the kinetic polarized Sunyaev Zel'dovich (kpSZ) effect. In this paper, we forecast the ability of future CMB and galaxy surveys to detect the kpSZ effect, finding that a statistically significant detection is within the reach of planned experiments. We further introduce a quadratic estimator for the square of the peculiar velocity field based on a galaxy survey and CMB polarization. Finally, we outline how the kpSZ effect is a probe of cosmic birefringence and primordial non-Gaussianity, forecasting the reach of future experiments.
FAST Observations of an Extremely Active Episode of FRB 20201124A. III. Polarimetry
Authors: Jiang Jin-Chen , Wang Wei-Yang , Xu Heng , Xu Jiang-Wei , Zhang Chun-Feng , Wang Bo-Jun , Zhou De-Jiang , Zhang Yong-Kun , Niu Jia-Rui , Lee Ke-Jia , Zhang Bing , Han Jin-Lin , Li Di , Zhu Wei-Wei , Dai Zi-Gao , Feng Yi , Jing Wei-Cong , Li Dong-Zi , Luo Rui , Miao Chen-Chen , Niu Chen-Hui , Tsai Chao-Wei , Wang Fa-Yin , Wang Pei , Xu Ren-Xin , Yang Yuan-Pei , Yang Zong-Lin , Yao Ju-Mei , Yuan Mao
Published: October 2022

As the third paper in the multiple-part series, we report the statistical properties of radio bursts detected from the repeating fast radio burst (FRB) source FRB 20201124A with the Five-hundred-meter Aperture Spherical radio Telescope during an extremely active episode between the 25th and 28th of September 2021 (UT). We focus on the polarization properties of 536 bright bursts with S/N > 50. We found that the Faraday rotation measures (RMs) monotonically dropped from −579 to −605 rad m−2 in the 4 day window. The RM values were compatible with the values (−300 to −900 rad m−2) reported 4 months ago. However, the RM evolution rate in the current observation window was at least an order of magnitude smaller than the one (∼500 rad m−2 day−1) previously reported during the rapid RM-variation phase, but is still higher than the one (≤1 rad m−2 day−1) during the later RM no-evolution phase. The bursts of FRB 20201124A were highly polarized with the total degree of polarization (circular plus linear) greater than 90% for more than 90% of all bursts. The distribution of linear polarization position angles (PAs), degree of linear polarization (L/I) and degree of circular polarization (V/I) can be characterized with unimodal distribution functions. During the observation window, the distributions became wider with time, i.e., with larger scatter, but the centroids of the distribution functions remained nearly constant. For individual bursts, significant PA variations (confidence level 5σ) were observed in 33% of all bursts. The polarization of single pulses seems to follow certain complex trajectories on the Poincaré sphere, which may shed light on the radiation mechanism at the source or the plasma properties along the path of FRB propagation.
Structure of international trade hypergraphs
Authors: Yi Sudo , Lee Deok-Sun
Published: October 2022

We study the structure of the international trade hypergraph consisting of triangular hyperedges representing the exporter–importer–product relationship. Measuring the mean hyperdegree of the adjacent vertices, we first find its behaviors different from those in the pairwise networks and explain the origin by tracing the relation between the hyperdegree and the pairwise degree. To interpret the observed hyperdegree correlation properties in the context of trade strategies, we decompose the correlation into two components by identifying one with the background correlation remnant even in the exponential random hypergraphs preserving the given empirical hyperdegree sequence. The other component characterizes the net correlation and reveals the bias of the exporters of low hyperdegree towards the importers of high hyperdegree and the products of low hyperdegree, which information is not readily accessible in the pairwise networks. Our study demonstrates the power of the hypergraph approach in the study of real-world complex systems and offers a theoretical framework.
Fault location method of Distributed Generation Sources in Distribution Networks based on optimal configuration of voltage sag monitoring points
Authors: Zhang Yong , zhan Hongxia , zhang Hao , Sun Yubo
Published: October 2022

In order to evaluate the fault location performance under the optimal configuration scheme of Power Quality Monitoring System(PQMS) monitoring points with Distributed Generation(DG) in, a fault location method based on successive binary search was proposed. Firstly, the influence of DG on traditional optimal configuration is analyzed, and the optimal configuration improvement strategy for DG access is proposed. The function relation between node voltage and fault distance under DG access is analyzed, and the ratio variation relation caused by voltage variation between monitoring points is used to reflect the characteristics of slight variation of electrical quantity, and the ranging evaluation function is established. In order to avoid the setting of convergence threshold, the disadvantage of setting fixed threshold is eliminated. Based on the mean ranging error, several feasible monitoring point configuration schemes are evaluated for ranging performance and the optimal configuration scheme for fault location performance is obtained. The 4-node system verifies that the ranging method does not need to set fixed convergence threshold. In the improved IEEE14 node system, this feature can be used to evaluate the positioning performance of four different monitoring point configuration schemes, and finally obtain the optimal positioning performance configuration scheme.
Maximum power point tracking of photovoltaic array based on improved Particle Swarm Optimization Algorithm
Authors: Lai GuangZhi , Li HaoRan , Zhang ChangZhi , Zhang YiHao , Wang ZhiJin
Published: October 2022

With the vigorous development of the photovoltaic industry, how to improve the efficiency of photovoltaic power generation has become an important issue, among which partial shadow occlusion is an important reason affecting the efficiency. The efficiency of photovoltaic power generation can be effectively improved by adopting the maximum power point tracking method (MPPT), but the traditional MPPT method is not ideal in the partial shadow occlusion of the photovoltaic array. To solve this problem, this paper proposes an improved particle swarm optimization method to effectively improve the tracking efficiency of MPPT when multiple peaks appear in the photovoltaic arrays power curve (P-V) under the partial shadow. The proposed method improves the learning factor of the traditional particle swarm optimization algorithm and designs the initial position of the particles according to the characteristics of the photovoltaic array. By adding the particle elimination mechanism, the number of particles changes dynamically, and the tracking speed of the algorithm for the maximum power of the photovoltaic array is improved. Through the result of the simulation, it is not difficult to get the conclusion that the improved particle swarm optimization algorithm can effectively improve the performance of the photovoltaic system under partial shadows.
Technical Research on New Transmission Conductor in Medium Ice Area
Authors: Pang Wei
Published: October 2022

In this paper, aluminum conductor steel reinforced(ACSR), high conductivity aluminum conductor steel reinforced, heat-resisting aluminum alloy conductor steel reinforced, and all aluminum alloy conductor are compared and analyzed in detail from the electrical characteristics, mechanical characteristics, and annual cost. Finally, combined with factors such as production process and construction technology, the transmission line conductor that is most suitable for a 15mm medium ice area is recommended. It provides a reference for the selection of transmission lines in future design.
The Optimization Research on Control Rule of Submersible Linear Motor Double-Acting Pump
Authors: Lu Jin-Jin , Zhong Xiao-Pu , Huang Ya-Nong , Yi Xiao-Jun
Published: October 2022

The paper takes one submersible linear motor double-acting pump as a research object. A relationship of linear motor output capability and its controls parameters is concluded by building a model. The oil production system control rule is researched by optimizing voltage, frequency and other control parameters. The results showed that a way by adjusting the output voltage and frequency can improve output capability of linear motor effectively and expand the oil production depth and application range of oil production system. Changing the maximum speed of the actuator through frequency has a great influence on the change of the maximum thrust required by the linear motor, because the change of speed has a great influence on the resistance along the path. The submersible linear motor double-acting pump oil production system is more suitable for deep Wells with less oil production.
A Review of Research on Transformer DC Bias Caused by HVDC Transmission
Authors: Zhao Guoliang , Qiao Guangyao , Yu Zhiyong , Chen Tian , Wang Yue
Published: October 2022

The construction of AC and DC transmission in China is accelerating. And the grid is getting closer, which will make the grid structure strong. However, the tightly connected power grid is more vulnerable to space weather and HVDC. Now, the researches on transformer DC bias were summarized, and the researching methods and achievements were analyzed. The main reasons and basic theory were introduced, and so did the influences to transformer. The method is generally to establish a corresponding calculation model through actual measurement, simulation and calculation, and limiting, isolating, injecting DC current are main restraining measures.
Research on grid-connected distributed generation considering relay protection
Authors: Li Yingliang , Sun Xiyao , Cai Heming , Liu Mengxi , Yang Yi
Published: October 2022

The access of distributed generation can cause some impacts on the distribution network, especially the change of the magnitude and direction of the short-circuit current may cause the relay protection device in the system to refuse or malfunction. Aiming at this problem, a mathematical model id founded in this paper, whose target is the maximum capacity of distributed generation. Besides normal constraints such as the node voltage and the total capacity, the current protection constraint is also taken into account. The genetic algorithm is used to optimize the capacity and location of the distributed generation in the IEEE33 bus distribution system model, and the obtained results verify the importance of taking into account the relay protection constraint.
Power grid practice of suppressing transient overvoltage of sending-end system by ultra high voltage direct current control parameters
Authors: Yang Mingkai , Li Yuanyuan , Fang Baomin , Zhang Xin , Chen Chunmeng
Published: October 2022

The transient overvoltage off-grid problem of new energy in the sending-end network has become an important factor limiting the ultra high voltage direct current (UHVDC) transmission capacity. In this paper, the causes of transient overvoltage during the DC fault process is analysed firstly, then from the perspective of adjusting the reactive power consumption of the converter, taking the Qingyu UHVDC project in China as an actual simulation example, the influence of the DC control mode and current control parameters at the rectifier side on the transient overvoltage is deeply studied. Combined with the transient voltage evaluation results of the actual power grid, guiding suggestions for DC control strategies are given to improve the transmission capacity. The research results have important reference significance for improving the consumption of new energy and the transmission capacity of UHVDC projects.
Research and application of deformation measurement method of hydraulic turbine head cover
Authors: He Liangchao , Deng Weiqi
Published: October 2022

Aiming at the deformation of hydraulic turbine head cover during operation, a non-contact eddy current sensor is proposed. In this method, the turbine pit wall is taken as the static reference point, a fixed support is erected on it, and the eddy current probe is fixed at the other end of the support. Measure the gap change between the eddy current sensor probe and the head cover to calculate the absolute deformation of the head cover. The effectiveness of the proposed method is verified by taking the lifting amount test of hydraulic turbine head cover in a power plant as an example. The results show that this method has the characteristics of simple test equipment, strong adaptability and high accuracy, and can be applied to the field test of hydraulic turbine head cover deformation.
Fixed-time Sliding Mode Control for Buck-Boost Converter
Authors: Zhou Yusheng , Liu Shilin , Wang Ning
Published: October 2022

To obtain stable state within the fixed time and reduce the influence of uncertain device parameters on the buck-boost converter, this paper proposes the fixed-time sliding mode control (FSMC) and fixed-time adaptive sliding mode control (FASMC). Firstly, we build the state-space average model on the basis of the continuous conduction mode (CCM) of the buck-boost converter. Secondly, the fixed-time sliding mode surface and FSMC are studied when the device parameters are known. By analyzing the Lyapunov stability, it has been proved that the system can reach a stable state within the fixed time, besides the maximum of the fixed time is merely determined by the parameters of the control strategy. Thirdly, when the system device parameters are unknown, the FASMC is developed ensuring the system can reach the adjacent domain of the equilibrium point within the fixed time. Finally, the effectiveness of the proposed control strategies was verified by the simulation experiments.