bluuebunny/crossref_metadata_2025 huggingface dataset:
Updates on the Hotspot and the Perseus-Pisces supercluster Excess Observed by the Telescope Array Experiment
Authors: Kim Jihyun , Ivanov Dmitri , Kawata Kazumasa , Sagawa Hiroyuki , Thomson Gordon
Published: April 2023

The Telescope Array (TA) experiment, the largest observatory studying ultra-high energy cosmic rays in the northern hemisphere, has reported evidence for two medium-scale anisotropies. The first, known as the TA hotspot, is an excess in the arrival direction distribution for events with energies greater than 5.7 × 1019eV. More recently, an additional excess of events with energies greater than 1019.4eV appearing in the direction of the Perseus-Pisces supercluster has been named the PPSC excess. In this presentation, we will update the status of the TA hotspot and the PPSC excess results using the most recent data measured by the TA surface detector array.
Status of the LHCf experiment
Authors: Ohashi Ken , Adriani Oscar , Berti Eugenio , Betti Pietro , Bonechi Lorenzo , Bongi Massimo , D’Alessandro Raffaello , Detti Sebastiano , Haguenauer Maurice , Itow Yoshitaka , Kasahara Katsuaki , Kitagami Yuga , Kondo Moe , Matsubara Yutaka , Menjo Hiroaki , Muraki Yasushi , Papini Paolo , Piparo Giuseppe , Ricciarini Sergio , Sako Takashi , Sakurai Nobuyuki , Scaringella Monica , Shimizu Yuki , Tamura Tadashi , Tiberio Alessio , Torii Shoji , Tricomi Alessia , Turner William C. , Yoshida Kenji
Published: April 2023

A precise understanding of hadronic interactions is essential to interpreting the mass composition of ultra-high energy cosmic rays from the results of air shower experiments. The Large Hadron Collier forward (LHCf) experiment aims to measure forward neutral particles for validation of hadronic interaction models adopted in air shower simulations. We already published the production cross sections of forward photons and neutrons for proton-proton collisions at √s=13 TeV. Recently, we showed a preliminary result of the energy spectrum of forward η mesons for proton-proton collisions at √s=13 TeV. Moreover, in September 2022, we had another data-taking for proton-proton collisions at √s=13.6 TeV. In data taking, we planned to obtain a number of π0and η candidates ten times larger for precise measurements and to perform the joint operation with ATLAS Roman pots and zero-degree calorimeters. Thanks to the joint operation with the ATLAS Roman pots, we can measure diffractive mass and neutral particles from diffractive dissociation simultaneously. Furthermore, energy resolution for neutrons is expected to be improved from 40% to 20% by combining the LHCf and the ATLAS zero-degree calorimeters. In this work, we report the status and prospects of the LHCf experiment.
AugerPrime status and prospects
Authors: Berat Corinne
Published: April 2023

The Pierre Auger Collaboration started a few years ago the AugerPrime project to increase the Surface Detector (SD) performance of the Pierre Auger Observatory. It aims to address the still open questions on the origin and composition of the highest energy cosmic rays by allowing a better identification of the nature of the primaries. The key element of this major upgrade is the capability of measuring the different components of extensive air showers, which will be significantly improved by the addition of a Surface Scintillator Detector (SSD) on each water-Cherenkov detector (WCD) constituting the SD. Moreover, the dynamic range of measurement is extended through an additional small photomultiplier tube inside the WCD. New electronics is processing the signals from the WCD and the SSD with higher sampling frequency and enhanced resolution. The scintillator module deployment started in 2019, and the new electronics in December 2020. The collected data allow for the evaluation of the first performances of the upgraded array and to adapt the whole data acquisition chain necessary for an efficient and sustainable operation of the Observatory. After the recall of the motivations for the upgrade, the main characteristics of the new detection setup are reviewed, as well as the status of its deployment and commissioning. The expected prospects are also discussed.
Influence of printing direction on 3D-printed vascular based self-healing cementitious composites
Authors: Wan Zhi , Xu Yading , Šavija Branko
Published: April 2023

Compared with other self-healing mechanisms, embedding vascular networks in cementitious matrix enables repairing wider cracks and performing multiple healing cycles. For vascular-based self-healing cementitious composites, additive manufacturing (AM) allows fabricating vascular structures with complex geometry. For Fused Filament Fabrication (FFF), printing direction has great influences on the properties of the 3D-printed vascular network. To timely release the healing agent when cracks occur, selecting the proper printing direction for the vascular network in self-healing concretes is necessary. In this work, two commercial printing filaments, i.e., polylactic acid (PLA) and polyvinyl alcohol (PVA), are used to create the vascular structures. The influence of printing direction on the dissolution of 3D-printed PVA structure is investigated. Besides, the flexural strength and water tightness of samples with PLA vascular printed in different printing directions are compared. After the 4-point bending tests, epoxy resin is manually injected into the vascular networks to seal the cracks. It is found that the strength recovery and the permeability of the cracked specimens are influenced by the printing direction due to the different crack closure after unloading.
Influencing factors to the capillary water uptake of (un)cracked cementitious materials
Authors: De Brabandere Laurena , Van Mullem Tim , Alderete Natalia , Baeyens Dries , De Belie Nele
Published: April 2023

Capillary water absorption tests are widely used in uncracked cementitious materials to assess the quality and durability. Due to the easy execution of the test, it is also frequently used to assess the self-healing efficiency of self-healing concrete and mortar. It is established that the presence of a crack significantly increases the water uptake by a specimen. However, it is not known how the crack width, healing agents and mix composition influence the capillary water absorption. In this research, for cylindrical mortar specimens with four different crack widths, both a capillary water absorption test and water permeability were test were executed in order to investigate the relation between these two test methods. After the first round of testing, cracked specimens were healed manually with polyurethane and methyl methacrylate and the capillary absorption test was performed again to investigate the sensitivity of the test method to different degrees of crack healing. Furthermore, prismatic specimens were cast to investigate the influence of crack creation and geometry. It was found that the crack width does not have an influence on the capillary absorption rate. However, the crack width has a significant influence on the water flow through the crack. As expected, manual healing with polyurethane is better in comparison to the sealing of the crack mouth with methyl methacrylate.
Study on COVD-19 epidemic prediction and distribution Strategy based on SIR Model
Authors: Liu Mengqi , Wang Pengyu , Zhao Zhifeng
Published: April 2023

Developing a more scientific COVID-19 response strategy has become a hot topic today. By sorting out a large amount of data, this paper predicts the spread law of the epidemic in Shanghai, Beijing, and Changchun in May, summarizing the key factors related to the spread of the epidemic and human immunity, using a tool to process and fitting the data, obtaining the spread law of the COVID-19 outbreak in the three cities under the epidemic, and establishing the SIR Infectious disease model. The development of the epidemic situation in the above towns was analyzed and predicted by linear fitting.

In than in Shanghai, Beijing, and Changchun, three cities the size of the population, social and economic situation, policy enforcement, and other factors, we select the optimal strategy of Shanghai medical collections as the research object to analyze the degree of Shanghai regional deficiencies, and supplies reasonable dispatch by using principal component analysis and cluster analysis method.
Die Beikostzeit – eine kulinarische Entdeckungsreise
für die ganze Familie
Authors: Stadelmann Natalie
Published: April 2023

Die Zeit der ersten Beikost ist für jedes Kind ein großer Schritt
zur Selbstständigkeit. Und ein Abenteuer für die ganze Familie.
Beim Forum Hebammenarbeit 2023 in Mainz betrachtet Natalie Stadelmann
Ernährungstrends und wissenschaftliche Empfehlungen und vermittelt
praxisnah, wie eine bewusste, bedürfnisgerechte, individuell angepasste
und ausgewogene Ernährung ergänzend zur Mutter- oder
Säuglingsmilch aussieht.
Identification of ADA as a Biomarker for Atypical Epstein Barr Virus
Infection in Children
Authors: Shi Ting , Huang Linlin , Zhang Wangsheng , Shi Wenxin , Wu Jiahui , Bian Yuanxi , Jiang Yanqun , Tian Jianmei
Published: April 2023

Objective This study aims to explore the ability of adenosine deaminase
(ADA) to discriminate atypical Epstein Barr virus (EBV) infection in children
from acute febrile illness.

Methods All children admitted to the Children’s Hospital of
Soochow University between 2018 and 2019, who were acute febrile patients and
subjected to the plasma EBV-DNA polymerase chain reaction (PCR) and indirect
immunofluorescence (IIF) assay for EBV-specific antibodies assays. The
diagnostic value of each detection index was compared by the area under the ROC
curve.

Results In children with atypical Epstein Barr virus infection, the
sensitivity, specificity, positive predictive value, negative predictive value
and Youden index were 62.87%, 100.00%,100.00%,
61.73% and 0.63 for EBV-DNA PCR assay, 80.84%, 100.00%,
100.00%, 75.76% and 0.81 for VCA-IgG avidity and 89.22%,
87.00%, 91.98%, 82.86% and 0.76 for ADA. VCA-IgG avidity
(AUC=0.904, P<0.01) and ADA (AUC=0.881, P<0.01)
assays had the great diagnostic efficiency. In addition, the sensitivity,
specificity and AUC were 92.75%,91.43% and 0.921(95%CI:
0.856–0.985) for ADA in the course≤3 days group,
respectively.

Conclusions ADA has a good diagnostic value in the early stage of atypical
EBV infection, and is not affected by primary EBV infection and
reactivation.

Schlüsselwörter Adenosine deaminase, Epstein -Barr virus,
Biomarker, children.
Silyl Esters as Reactive Intermediates in Organic Synthesis
Authors: Adler Marc J. , D’Amaral Melissa C. , Andrews Keith G. , Denton Ross
Published: April 2023

Silyl esters have been exploited as metastable reaction intermediates, both purposefully and unintentionally, since at least the 1960s. Their reactivity is broadly related to the substituents on the silicon, and in this way their properties can be readily modulated. Silyl esters have unique reactivity profiles that have been used to generate downstream products of a range of functionalities, and because of this many excellent methods for the synthesis of a variety of value-added chemicals have been developed. Furthermore, because of the frequent use of hydrosilanes as terminal reductants in catalytic processes, silyl ester intermediates are likely more commonly utilized by synthetic chemists than currently realized. This review comprehensively summarizes the reactions known to take advantage of reactive silyl ester intermediates and discusses examples of catalytic reactions that proceed in an unanticipated manner through silyl ester intermediates.

1 Introduction

2 Synthesis of Silyl Esters

3 Making Amides from Silyl Esters

3.1 Amidation Using Chlorosilanes

3.2 Amidation Using Azasilanes

3.3 Amidation Using Oxysilanes

3.4 Amidation Using Hydrosilanes

3.5 Amine Formation via Amidation/Reduction

3.6 Miscellaneous

4 Mechanistic Investigations of Amidation

4.1 Mechanism of Amidation Using Chlorosilanes

4.2 Mechanism of Amidation Using Hydrosilanes

4.3 Mechanism of Amidation Using Oxy- or Azasilanes

5 Making Esters from Silyl Esters

6 Making Aldehydes, Alcohols, Amines, and Alkanes via Reduction

6.1 Aldehyde Synthesis by Metal-Free Reduction

6.2 Aldehyde Synthesis by Metal-Mediated Reduction

6.3 Alcohol Synthesis by Metal-Mediated Reduction

6.4 Amine Synthesis

6.5 Alkane Synthesis by Metal-Free Reduction

7 Making Acid Chlorides from Silyl Esters

8 In Situ Generated Silyl Esters and Ramifications for Catalysis

9 Conclusion
Induction of Migration and Collagen Synthesis in Human Gingival Fibroblasts Using Periodontal Ligament Stem Cell Conditioned Medium
Authors: Banlue Akkapol , Kaewmuangmoon Jirattikarn , Janebodin Kajohnkiart , Tansriratanawong Kallapat
Published: April 2023

Objective This study aimed to examine the effect of periodontal ligament stem cell conditioned medium (PDLSC-CM) on human gingival fibroblast (HGF) migration and collagen synthesis.

Materials and Methods To assess cell viability, we extracted PDLSC-CM, and the total derived protein concentration was adjusted to 12.5 to 200 µg/mL, followed by treatment with HGFs. The viability of HGFs was observed for 24 hours using the MTT assay. Cell migration was monitored for 24 to 48 hours by wound healing and Boyden chamber assays. Collagen synthesis from HGFs was examined by picrosirius red dye and real-time polymerase chain reaction (PCR) to measure collagen type I and III gene expression for 7 to 10 days. A comparison among the groups was assessed using a one-way analysis of variance (ANOVA) and Bonferroni post hoc test, with the exception of the cell viability assay, which was subjected to Welch's test and Dunnett's T3 post hoc test.

Results HGF viability was significantly enhanced by 12.5, 25, and 50 µg/mL PDLSC-CM. The HGFs treated with 50 µg/mL PDLSC-CM promoted cell migration as shown by wound healing and Boyden chamber assays. At this concentration, collagen synthesis increased at 10 days. Collagen type I gene expression increased by 1.6-fold (p < 0.001) and 4.96-fold (p < 0.001) at 7 and 10 days, respectively. Collagen type III gene expression showed an increase of 1.76-fold (p < 0.001) and 6.67-fold (p < 0.001) at the same time points.

Conclusion Our study suggested that a low concentration of PDLSC-CM at 50 µg/mL has given an amelioration of HGFs providing for periodontal wound healing and periodontal regeneration, particularly migration and collagen synthesis.
Standardization of Latency and Amplitude Values of Short, Middle and Long Latency Auditory Evoked Potentials in Adults
Authors: Pelaquim Andressa , Sanfins Milaine Dominici , Fornazieri Marco Aurélio
Published: April 2023

Introduction Auditory processing refers to the efficiency and effectiveness with which the central auditory nervous system uses auditory information. Middle- and long-latency auditory evoked potentials are objective electrophysiological tests that can complement the diagnosis of alterations involving central auditory processing.

Objective To standardize latency and amplitude values for short-, middle-, and long-latency auditory evoked potentials in adults with normal hearing thresholds.

Methods This is a cross-sectional study. Thirty-three adults with normal hearing thresholds, without hearing complaints, and with normal central auditory processing were evaluated. All underwent basic audiological evaluation, central auditory processing assessment, and short-, middle-, and long-latency auditory evoked potentials.

Results Absolute latency and interpeak values for middle- and long-latency auditory evoked potentials were lower than internationally suggested. However, for the brainstem auditory evoked potential, the means were within the range considered as normal, as suggested in the equipment.

Conclusion The present study provided measurements of normal latencies and amplitudes for short-, middle-, and long-latency auditory evoked potentials in adults.
Etiology and Epidemiology of Nasal Bone Fractures in Patients Referred to the Otorhinolaryngology Section, 2019
Authors: Davari Rahim , Pirzadeh Akbar , Sattari Fatemeh
Published: April 2023

Introduction One of the most observed diseases in the otorhinolaryngology emergency, compared with the other facial fractures, is related to nasal bone fractures (NBFs). The peak of incidence is seen in the age group ranging from 11 to 30 years old.

Objective The present evaluation was devoted to the etiology and epidemiological study of NBFs.

Methods In the present cross-sectional study, 376 patients with NBF were evaluated. The necessary information such as gender, age, education, job, causes of NBF, and clinical symptoms of patients have been recorded on the checklist.

Results The study revealed that 76.9% of the patients were male and 23.1% were female; 37.5% of all patients were self-employed, and most of them were from urban areas. Traffic accident (26.6%) and falling (25.5%) were the main reasons for NBF. The most common clinical symptoms for NBF were tenderness (96%; n = 361), nasal swelling (90.4%; n = 340), and deformity (89.4%; n = 336).

Conclusion The results showed that the incidence of NBFs in young men without higher education level and self-employed were high which can be related to the traffic accidents and fights. Also, falls, beatings and accidental hit are the most common causes of NBFs among women. Therefore, to decrease the incidence of otorhinolaryngology trauma, training about the general life skill and providing awareness about using personal safety equipment and measures should be increased at the future.
Technologies Applied to the Mental Health Care of Pregnant Women: A Systematic Literature Review
Authors: Carvalho Laís Lage de , Teixeira Júlia Magna da Silva , Unger Roberto José Gervásio , Motti Vivian Genaro , Lovisi Giovanni Marcos , Grincenkov Fabiane Rossi dos Santos
Published: April 2023

Objective: This article aims to review the literature regarding the use of technologies to promote mental health for pregnant women. We seek to: understand the strategies that pregnant women use for mental health care. Also, we investigate the existence of scientific evidence that validates such practices.

Methods: This study follows the PRISMA guidelines for systematic reviews. We analyze 27 studies published between 2012 and 2019. We include publications in Portuguese, English, and Spanish.

Results: The results revealed several different possibilities to use technology, including the use of text messages and mobile applications on smartphones. Mobile applications are the most commonly used approaches (22.5%). Regarding the strategies used, cognitive-behavioral approaches, including mood checks, relaxation exercises, and psychoeducation comprised 44.12% of the content.

Conclusion: There is a need for further investigation and research and development efforts in this field to better understand the possibilities of intervention in mental health in the digital age.
Advance Care Planning and Parent-Reported End-of-Life Outcomes in the Neonatal Intensive Care Unit
Authors: Lin Matthew , Williams David , Vitcov Giselle , Sayeed Sadath , DeCourcey Danielle D. , Wolfe Joanne , Cummings Christy
Published: April 2023

Objective This study aimed to evaluate the impact of advance care planning (ACP) on parent-reported end-of-life (EOL) outcomes in the neonatal intensive care unit (NICU).

Study Design Single-center, cross-sectional mixed-methods survey study of bereaved parents who experienced the death of a child in the Boston Children's Hospital NICU between 2010 and 2021. Logistic regression, chi-square test, Fisher's exact test, and Wilcoxon rank-sum test were used to evaluate the relationship between ACP and parent-reported EOL outcomes. Qualitative content was analyzed through inductive coding.

Results A total of 40/146 (27%) of eligible parents responded to our survey. There was a significant association between ACP and improved EOL care processes and parental satisfaction with communication. Parents with ACP were more likely to report goal-concordant care and higher levels of perceived shared decision-making. Qualitatively, emerging themes in parents' descriptions of goal-concordant care included misaligned expectations and communication. Emerging themes for parental preparedness included infant symptoms, logistical aspects, impact on parents, and degrees of preparedness. For decisional regret, the primary theme was reevaluating supports.

Conclusion ACP is associated with improved EOL care outcomes and parents qualitatively conceptualize goal-concordant care, preparedness for their child's death, and decisional regret in nuanced ways. Families should have the opportunity to participate in ACP discussions that meet their unique communication and decision-making needs.

Key Points
Integrating Oldenburg’s concept of place and Soja’s concept of space: a spatial enquiry of denial, repression, and closure in Ishiguro’s “The Remains of the Day”
Authors: Maran Aishwarya , J Michael Raj
Published: April 2023

Spatial enquiry in literature has opened new doors for understanding the relationship between physical and mental space. This paper analyses how an individual’s sense of space can influence their understanding of themselves and others. This study identifies the similarities between Ray Oldenburg’s concept of place and Edward Soja’s concept of space. Moreover, it integrates both theories by locating Oldenburg’s triad of place (home, workplace, and third place) as a part of Soja’s concept of real space (firstspace). The lack of discernibility between home and workspace exerts itself in protagonist Stevens’ obsession with his profession. This paper also examines how disorientation in the trifold conception of place causes Stevens to be an emotionally and spatially repressed character. The study elaborates on the role of third place and thirdspace. It also analyses Steven’s six-day journey into the countryside as an introspective journey into his past. This study aims to find how social interactions in the third place have helped Stevens unlearn and relearn hegemonically influenced ideologies on duty and dignity. Further, it helps Stevens resolve his denial and repression, properly channelling the flow of spatial energy. This study also identifies thirdspace as a transformative space that helps Stevens find closure and accept his regretful past.
Deep mining of the protein energy landscape
Authors: Wand A. Joshua
Published: April 2023

For over half a century, it has been known that protein molecules naturally undergo extensive structural fluctuations, and that these internal motions are intimately related to their functional properties. The energy landscape view has provided a powerful framework for describing the various physical states that proteins visit during their lifetimes. This Perspective focuses on the commonly neglected and often disparaged axis of the protein energy landscape: entropy. Initially seen largely as a barrier to functionally relevant states of protein molecules, it has recently become clear that proteins retain considerable conformational entropy in the “native” state, and that this entropy can and often does contribute significantly to the free energy of fundamental protein properties, processes, and functions. NMR spectroscopy, molecular dynamics simulations, and emerging crystallographic views have matured in parallel to illuminate dynamic disorder of the “ground state” of proteins and their importance in not only transiting between biologically interesting structures but also greatly influencing their stability, cooperativity, and contribution to critical properties such as allostery.
Optimizing testing strategies for early detection of disease outbreaks in animal trade networks via MCMC
Authors: Ansari Sara , Heitzig Jobst , Moosavi Mohammad R.
Published: April 2023

The animal trades between farms and other livestock holdings form a complex livestock trade network. The movement of animals between trade actors plays an important role in the spread of infectious diseases among premises. Particularly, the outbreak of silent diseases that have no clinically obvious symptoms in the animal trade system should be diagnosed by taking special tests. In practice, the authorities regularly conduct examinations on a random number of farms to make sure that there was no outbreak in the system. However, these actions, which aim to discover and block a disease cascade, are yet far from the effective and optimum solution and often fail to prevent epidemics. A testing strategy is defined as making decisions about distributing the fixed testing budget N between farms/nodes in the network. In this paper, first, we apply different heuristics for selecting sentinel farms on real and synthetic pig-trade networks and evaluate them by simulating disease spreading via the SI epidemic model. Later, we propose a Markov chain Monte Carlo (MCMC) based testing strategy with the aim of early detection of outbreaks. The experimental results show that the proposed method can reasonably well decrease the size of the outbreak on both the realistic synthetic and real trade data. A targeted selection of an N/52 fraction of nodes in the real pig-trade network based on the MCMC or simulated annealing can improve the performance of a baseline strategy by 89%. The best heuristic-based testing strategy results in a 75% reduction in the average size of the outbreak compared to that of the baseline testing strategy.
Reservoir computing with noise
Authors: Nathe Chad , Pappu Chandra , Mecholsky Nicholas A. , Hart Joe , Carroll Thomas , Sorrentino Francesco
Published: April 2023

This paper investigates in detail the effects of measurement noise on the performance of reservoir computing. We focus on an application in which reservoir computers are used to learn the relationship between different state variables of a chaotic system. We recognize that noise can affect the training and testing phases differently. We find that the best performance of the reservoir is achieved when the strength of the noise that affects the input signal in the training phase equals the strength of the noise that affects the input signal in the testing phase. For all the cases we examined, we found that a good remedy to noise is to low-pass filter the input and the training/testing signals; this typically preserves the performance of the reservoir, while reducing the undesired effects of noise.
The peculiar potential of transition metal dichalcogenides for thermoelectric applications: A perspective on future computational research
Authors: Özbal Sargın Gözde , Sarikurt Sevil , Sevinçli Hâldun , Sevik Cem
Published: April 2023

The peculiar potential transition metal dichalcogenides in regard to sensor and device applications have been exhibited by both experimental and theoretical studies. The use of these materials, thermodynamically stable even at elevated temperatures, particularly in nano- and optoelectronic technology, is about to come true. On the other hand, the distinct electronic and thermal transport properties possessing unique coherency, which may result in higher thermoelectric efficiency, have also been reported. However, exploiting this potential in terms of power generation and cooling applications requires a deeper understanding of these materials in this regard. This perspective study, concentrated with this intention, summarizes thermoelectric research based on transition metal dichalcogenides from a broad perspective and also provides a general evaluation of future theoretical investigations inevitable to shed more light on the physics of electronic and thermal transport in these materials and to lead future experimental research.
A sub-2 Kelvin cryogenic magneto-terahertz scattering-type scanning near-field optical microscope (cm-THz-sSNOM)
Authors: Kim R. H. J. , Park J.-M. , Haeuser S. J. , Luo L. , Wang J.
Published: April 2023

We have developed a versatile near-field microscopy platform that can operate at high magnetic fields and below liquid-helium temperatures. We use this platform to demonstrate an extreme terahertz (THz) nanoscope operation and to obtain the first cryogenic magneto-THz time-domain nano-spectroscopy/imaging at temperatures as low as 1.8 K, magnetic fields of up to 5 T, and with operation of 0–2 THz. Our Cryogenic Magneto-Terahertz Scattering-type Scanning Near-field Optical Microscope (or cm-THz-sSNOM) instrument is comprised of three main equipment: (i) a 5 T split pair magnetic cryostat with a custom made insert, (ii) a custom sSNOM instrument capable of accepting ultrafast THz excitation, and (iii) a MHz repetition rate, femtosecond laser amplifier for broadband THz pulse generation and sensitive detection. We apply the cm-THz-sSNOM to obtain proof of principle measurements of superconductors and topological semimetals. The new capabilities demonstrated break grounds for studying quantum materials that require an extreme environment of cryogenic operation and/or applied magnetic fields in nanometer space, femtosecond time, and THz energy scales.
Cerium-promoted conversion of dinitrogen into high-energy-density material CeN6 under moderate pressure
Authors: Wang Yuanyuan , Li Zhihui , Niu Shifeng , Yi Wencai , Liu Shuang , Yao Zhen , Liu Bingbing
Published: April 2023

Synthesis pressure and structural stability are two crucial factors for highly energetic materials, and recent investigations have indicated that cerium is an efficient catalyst for N2 reduction reactions. Here, we systematically explore Ce–N compounds through first-principles calculations, demonstrating that the cerium atom can weaken the strength of the N≡N bond and that a rich variety of cerium polynitrides can be formed under moderate pressure. Significantly, P1̄-CeN6 possesses the lowest synthesis pressure of 32 GPa among layered metal polynitrides owing to the strong ligand effect of cerium. The layered structure of P1̄-CeN6 proposed here consists of novel N14 ring. To clarify the formation mechanism of P1̄-CeN6, the reaction path Ce + 3N2 → trans-CeN6 → P1̄-CeN6 is proposed. In addition, P1̄-CeN6 possesses high hardness (20.73 GPa) and can be quenched to ambient conditions. Charge transfer between cerium atoms and N14 rings plays a crucial role in structural stability. Furthermore, the volumetric energy density (11.20 kJ/cm3) of P1̄-CeN6 is much larger than that of TNT (7.05 kJ/cm3), and its detonation pressure (128.95 GPa) and detonation velocity (13.60 km/s) are respectively about seven times and twice those of TNT, and it is therefore a promising high-energy-density material.
Simulation and comparison between multi-fluid and kinetic models of impurity transport
Authors: Wang Jin , Chen YiPing , Wang Liang , Gao Wei , Wu Zhenwei , Zhang Ling
Published: April 2023

Impurity transport is a highly significant research topic in international fusion plasma simulations, which are mainly simulated by numerical codes at present. Most of the numerical simulation codes for impurity transport adopt multi-fluid or kinetic model to treat impurity particles. Therefore, it is necessary to select a suitable transport model for the simulation process. For impurity particles, if the mean free path of particles λ is much smaller than the gradient scale length of particles λ g, it is sufficient to treat the particles by the multi-fluid model. However, under some conditions, λ will be much larger than λ g. The applicability of the fluid model is limited when λ is larger than or equal to λ g. A comparison with the simulations on impurity transport treated with multi-fluid and kinetic models is necessary, respectively. In this study, the simulation results of carbon (C) impurity transport in the EAST scrape-off layer with the 2D edge plasma fluid code SOLPS-ITER and the 2D Monte Carlo impurity transport code DIVIMP are compared. The comparison between the distributions of carbon impurities ( C 0 ∼ C + 6) in the different ionization states and the CIII emissivity predicted by SOLPS-ITER and DIVIMP shows that the density distributions of carbon atoms C 0 predicted by the SOLPS-ITER and DIVIMP codes are similar. However, for carbon ions in different ionization states, the variations between the density distributions simulated from the SOLPS-ITER and DIVIMP codes can become larger with the increase in ionization states. DIVIMP performs slightly better than SOLPS-ITER in reproducing the shape of the CIII profile when drifts are switched off in SOLPS-ITER, but the difference is extremely small in terms of the uncertainties involved in these calculations.
Carbon nanotube fiber-based high-performance force and position sensors for smart fabrics and the Internet of things
Authors: Jeon Dae-Young , Park Jimin , Lee Changwoo , Kim Seung Min
Published: April 2023

Carbon nanotube (CNT) fibers are used in various applications, such as electrical cables, supercapacitors, physical sensors, artificial muscles, and electronic devices, due to their excellent mechanical, thermal, and electrical properties. Herein, the orientation-dependent electrical characteristics of a CNT fiber array were investigated. A force resistive sensor with good sensitivity and reliable operation was developed using the array and integrated with a real-time data storage and wireless monitoring system. In addition, a CNT fiber-based position sensor was developed for application in smart fabrics. This study introduces an easy-to-manufacture, low-cost, robust CNT fiber-based sensing platform that can be used with an open-source microcontroller for integration with the Internet of things.
Nonadiabatic transition probabilities for quantum systems in electromagnetic fields: Dephasing and population relaxation due to contact with a bath
Authors: Jovanovski Sara D. , Mandal Anirban , Hunt Katharine L. C.
Published: April 2023

We contrast Dirac’s theory of transition probabilities and the theory of nonadiabatic transition probabilities, applied to a perturbed system that is coupled to a bath. In Dirac’s analysis, the presence of an excited state |k0⟩ in the time-dependent wave function constitutes a transition. In the nonadiabatic theory, a transition occurs when the wave function develops a term that is not adiabatically connected to the initial state. Landau and Lifshitz separated Dirac’s excited-state coefficients into a term that follows the adiabatic theorem of Born and Fock and a nonadiabatic term that represents excitation across an energy gap. If the system remains coherent, the two approaches are equivalent. However, differences between the two approaches arise when coupling to a bath causes dephasing, a situation that was not treated by Dirac. For two-level model systems in static electric fields, we add relaxation terms to the Liouville equation for the time derivative of the density matrix. We contrast the results obtained from the two theories. In the analysis based on Dirac’s transition probabilities, the steady state of the system is not an equilibrium state; also, the steady-state population ρkk,s increases with increasing strength of the perturbation and its value depends on the dephasing time T2. In the nonadiabatic theory, the system evolves to the thermal equilibrium with the bath. The difference is not simply due to the choice of basis because the difference remains when the results are transformed to a common basis.
Transfer learning and multi-fidelity modeling of laser-driven particle acceleration
Authors: Djordjević B. Z. , Kim J. , Wilks S. C. , Ludwig J. , Myers C. , Kemp A. J. , Swanson K. K. , Zeraouli G. , Grace E. S. , Simpson R. A. , Rusby D. , Antoine A. F. , Bremer P.-T. , Thiagarajan J. , Anirudh R. , Williams G. J. , Ma T. , Mariscal D. A.
Published: April 2023

Computer models of intense, laser-driven ion acceleration require expensive particle-in-cell simulations that may struggle to capture all the multi-scale, multi-dimensional physics involved at reasonable costs. Explored is an approach to ameliorate this deficiency using a multi-fidelity framework that can incorporate physical trends and phenomena at different levels. As the basis for this study, an ensemble of approximately 8000 1D simulations was generated to buttress separate ensembles of hundreds of higher fidelity 1D and 2D simulations. Using transfer learning with deep neural networks, one can reproduce the results of more complex physics at a much lower cost. The networks trained in this fashion can, in turn, act as surrogate models for the simulations themselves, allowing for quick and efficient exploration of the parameter space of interest. Standard figures-of-merit were used as benchmarks such as the hot electron temperature, peak ion energy, conversion efficiency, and so on. We can rapidly identify and explore under what conditions differing fidelities become an important effect and search for outliers in feature space.
Enhanced mechanical properties of silicone hydrogels coated with metallic nanoparticles by using the laser-assisted process
Authors: Wuppaladhodi Vishnuvardhana , Yang Songlin , Pouri Hossein , Zhang Jin
Published: April 2023

Silicone hydrogels coated with metallic nanostructures have attracted extensive attention because of their versatile applications in biomedical devices. However, few studies have been reported for characterizing the mechanical behavior of silicone hydrogel under biaxial tensile stresses. In addition, compared to most chemical coating processes, the deposition of nanostructures on silicone hydrogel by using a laser-assisted process can avoid chemical impurities and additional sterilization processes. Herein, a laser-assisted process is used for producing polyvinylpyrrolidone (PVP) modified silver (Ag) nanoparticles (Ag-PVP NPs), which are further deposited on silicone hydrogel. In the uniaxial mechanical test, the value of Young's modulus of Ag-PVP NP coated silicone hydrogels is increased as compared to that of silicone hydrogel. The energy absorption of silicone hydrogel and Ag-PVP NP coated silicone hydrogel measured by the uniaxial mechanical test is 15.137 ± 0.412 and 22.014 ± 0.186 MJ/m3, respectively. Furthermore, the biaxial test is applied to study the mechanical properties of silicone hydrogel coated with Ag-PVP NPs. Meanwhile, a constitutive model was applied to further understand the mechanical behavior of silicone hydrogel coated with Ag-PVP NPs. The result indicates that silicone hydrogel coated with Ag-PVP NPs shows a pseudo-elastic nonlinear behavior which is similar to collagen-based tissue substitutes.
Information-theoretical analysis of statistical measures for multiscale dynamics
Authors: Asuke Naoki , Yamagami Tomoki , Mihana Takatomo , Röhm André , Horisaki Ryoichi , Naruse Makoto
Published: April 2023

Multiscale entropy (MSE) has been widely used to examine nonlinear systems involving multiple time scales, such as biological and economic systems. Conversely, Allan variance has been used to evaluate the stability of oscillators, such as clocks and lasers, ranging from short to long time scales. Although these two statistical measures were developed independently for different purposes in different fields, their interest lies in examining the multiscale temporal structures of physical phenomena under study. We demonstrate that from an information-theoretical perspective, they share some foundations and exhibit similar tendencies. We experimentally confirmed that similar properties of the MSE and Allan variance can be observed in low-frequency fluctuations (LFF) in chaotic lasers and physiological heartbeat data. Furthermore, we calculated the condition under which this consistency between the MSE and Allan variance exists, which is related to certain conditional probabilities. Heuristically, natural physical systems including the aforementioned LFF and heartbeat data mostly satisfy this condition, and hence, the MSE and Allan variance demonstrate similar properties. As a counterexample, we demonstrate an artificially constructed random sequence, for which the MSE and Allan variance exhibit different trends.
A diagnostic to measure time-resolved atom column density and Doppler temperature in atomic vapors produced by laser ablation
Authors: Schauer M. M. , Paisner J. A. , Stevens G. D.
Published: April 2023

We report on the development of a diagnostic to measure the time-resolved column density and Doppler temperature of atomic vapors produced by laser ablation. The diagnostic is based on the strong frequency dependence of the atomic susceptibility near an electronic transition in the interrogated atomic species. Interference on the face of a fast photodetector between the several frequency components present in a sinusoidally phase-modulated probe beam will produce a time signature uniquely determined by the column density of atoms in the probed atomic state and the Doppler temperature of the atomic vapor. With the extensive, high precision atomic spectroscopy data available in the literature, it is possible to model the vapor and extract the desired parameters through comparison of the model result with the experimental data.
Thermal degradation comparison of delta-doped GaAs tunnel junctions using Si and Te n-type dopants
Authors: Madarang May Angelu , Chu Rafael Jumar , Kim Yeonhwa , Lung Quang Nhat Dang , Ju Eunkyo , Choi Won Jun , Jung Daehwan
Published: April 2023

Tunnel junctions (TJs) are essential for high-performance multijunction solar cells to act as transparent low resistance paths for carriers to travel between adjacent cells. However, TJs typically exhibit highly degraded tunneling performance due to unwanted dopant out-diffusion during top cell growth. In this study, GaAs TJs with Si and Te delta-doping (δ-doping) were grown via solid source molecular beam epitaxy to investigate the tunneling performance and thermal stability. While Si δ-doped TJs exhibited typical tunneling characteristics with an Esaki peak current density of 173 A/cm2, Te δ-doped TJs revealed 1.5 A/cm2 at Vbias = 100 mV without negative resistance. It was found that the performance degradation after annealing at 600 °C for 90 min was significantly higher for TJs with Si δ-doping than for Te. Secondary ion mass spectroscopy measurements reveal that Te shows no clear signs of dopant diffusion while Si exhibited significant out-diffusion in the active TJ layer after thermal annealing. The superior thermal stability of Te compared to Si proves to be advantageous as an alternative n-type dopant for high temperature and long duration grown multi-junction solar cells.
Critical assessment of various particle Fokker–Planck models for monatomic rarefied gas flows
Authors: Gorji Hossein
Published: April 2023

In the past decade, the particle-based Fokker–Planck (FP) method has been extensively studied to reduce the computational costs of the direct simulation Monte Carlo method for near-continuum flows. The FP equation describes a continuous stochastic process through the combined effects of systematic forces and random fluctuations. A few different FP models have been proposed to fulfill consistency with the Boltzmann equation, but a comprehensive comparative study is needed to assess their performance. The present paper investigates the accuracy and efficiency of four different FP models—Cubic-FP, ellipsoidal-statistical FP (ES-FP), and quadratic entropic FP (Quad-EFP)—under rarefied conditions. The numerical test cases include one-dimensional Couette and Fourier flows and an argon flow past a cylinder at supersonic and hypersonic velocities. It is found that the Quad-EFP model gives the best accuracy in low-Mach internal flows, whereas the ES-FP model performs best at predicting shock waves. In terms of numerical efficiency, the Linear-FP and ES-FP models run faster than the Cubic-FP and Quad-EFP models due to their simple algebraic nature. However, it is observed that the computational advantages of the FP models diminish as the spatiotemporal resolution becomes smaller than the collisional scales. In order to take advantage of their numerical efficiency, high-order joint velocity-position integration schemes need to be devised to ensure the accuracy of FP models with very coarse resolution.
Porting fragmentation methods to GPUs using an OpenMP API: Offloading the resolution-of-the-identity second-order Møller–Plesset perturbation method
Authors: Pham Buu Q. , Carrington Laura , Tiwari Ananta , Leang Sarom S. , Alkan Melisa , Bertoni Colleen , Datta Dipayan , Sattasathuchana Tosaporn , Xu Peng , Gordon Mark S.
Published: April 2023

Using an OpenMP Application Programming Interface, the resolution-of-the-identity second-order Møller–Plesset perturbation (RI-MP2) method has been off-loaded onto graphical processing units (GPUs), both as a standalone method in the GAMESS electronic structure program and as an electron correlation energy component in the effective fragment molecular orbital (EFMO) framework. First, a new scheme has been proposed to maximize data digestion on GPUs that subsequently linearizes data transfer from central processing units (CPUs) to GPUs. Second, the GAMESS Fortran code has been interfaced with GPU numerical libraries (e.g., NVIDIA cuBLAS and cuSOLVER) for efficient matrix operations (e.g., matrix multiplication, matrix decomposition, and matrix inversion). The standalone GPU RI-MP2 code shows an increasing speedup of up to 7.5× using one NVIDIA V100 GPU with one IBM 42-core P9 CPU for calculations on fullerenes of increasing size from 40 to 260 carbon atoms using the 6-31G(d)/cc-pVDZ-RI basis sets. A single Summit node with six V100s can compute the RI-MP2 correlation energy of a cluster of 175 water molecules using the correlation consistent basis sets cc-pVDZ/cc-pVDZ-RI containing 4375 atomic orbitals and 14 700 auxiliary basis functions in ∼0.85 h. In the EFMO framework, the GPU RI-MP2 component shows near linear scaling for a large number of V100s when computing the energy of an 1800-atom mesoporous silica nanoparticle in a bath of 4000 water molecules. The parallel efficiencies of the GPU RI-MP2 component with 2304 and 4608 V100s are 98.0% and 96.1%, respectively.
Temporal localized states and square-waves in semiconductor micro-resonators with strong time-delayed feedback
Authors: Koch Elias R. , Seidel Thomas G. , Javaloyes Julien , Gurevich Svetlana V.
Published: April 2023

In this paper, we study the dynamics of a vertically emitting micro-cavity operated in the Gires–Tournois regime that contains a semiconductor quantum-well and that is subjected to strong time-delayed optical feedback and detuned optical injection. Using a first principle time-delay model for the optical response, we disclose sets of multistable dark and bright temporal localized states coexisting on their respective bistable homogeneous backgrounds. In the case of anti-resonant optical feedback, we identify square-waves with a period of twice the round-trip in the external cavity. Finally, we perform a multiple time scale analysis in the good cavity limit. The resulting normal form is in good agreement with the original time-delayed model.
Quantum Stoner–Wohlfarth model of two-dimensional single-domain magnets
Authors: Ibrahim Essa M. , Zhang Shufeng
Published: April 2023

The Stoner–Wohlfarth model is a classical model for magnetic hysteresis of single-domain magnets. For two-dimensional (2D) magnets at finite temperatures, the Stoner–Wohlfarth model must be extended to include intrinsic strong spin fluctuations. We predict several fundamentally different hysteresis properties between 2D and 3D magnets. The magnetization switching diagram known as the astroid figure in the conventional Stoner–Wohlfarth model becomes highly temperature dependent and asymmetric with respect to the transverse and longitudinal magnetic fields. Our results provide new insights into the spintronics applications based on 2D magnetic materials.