bluuebunny/crossref_metadata_2025 huggingface dataset:
Metabarcoding the Antarctic Peninsula biodiversity using a multi-gene approach
Authors: Fonseca V G , Kirse A , Giebner H , Vause B J , Drago T , Power D M , Peck L S , Clark M S
Published: April 2022

Marine sediment communities are major contributors to biogeochemical cycling and benthic ecosystem functioning, but they are poorly described, particularly in remote regions such as Antarctica. We analysed patterns and drivers of diversity in metazoan and prokaryotic benthic communities of the Antarctic Peninsula with metabarcoding approaches. Our results show that the combined use of mitochondrial Cox1, and 16S and 18S rRNA gene regions recovered more phyla, from metazoan to non-metazoan groups, and allowed correlation of possible interactions between kingdoms. This higher level of detection revealed dominance by the arthropods and not nematodes in the Antarctic benthos and further eukaryotic diversity was dominated by benthic protists: the world’s largest reservoir of marine diversity. The bacterial family Woeseiaceae was described for the first time in Antarctic sediments. Almost 50% of bacteria and 70% metazoan taxa were unique to each sampled site (high alpha diversity) and harboured unique features for local adaptation (niche-driven). The main abiotic drivers measured, shaping community structure were sediment organic matter, water content and mud. Biotic factors included the nematodes and the highly abundant bacterial fraction, placing protists as a possible bridge for between kingdom interactions. Meiofauna are proposed as sentinels for identifying anthropogenic-induced changes in Antarctic marine sediments.
Impact of SARS-CoV-2 Gamma lineage introduction and COVID-19 vaccination on the epidemiological landscape of a Brazilian city
Authors: Banho Cecília Artico , Sacchetto Lívia , Campos Guilherme Rodrigues Fernandes , Bittar Cíntia , Possebon Fábio Sossai , Ullmann Leila Sabrina , Marques Beatriz de Carvalho , da Silva Gislaine Ceslestino Dutra , Moraes Marília Mazzi , Parra Maisa Carla Pereira , Negri Andreia Francesli , Boldrin Ana Carolina , Barcelos Michela Dias , dos Santos Thayza M. I. L. , Milhim Bruno H. G. A. , Rocha Leonardo Cecílio , Dourado Fernanda Simões , dos Santos Andresa Lopes , Ciconi Victoria Bernardi , Patuto Caio , Versiani Alice Freitas , da Silva Rafael Alves , de Oliveira Lobl Edoardo Estevam , Hernandes Victor Miranda , Zini Nathalia , Pacca Carolina Colombelli , Estofolete Cássia Fernanda , Ferreira Helena Lage , Rahal Paula , Araújo João Pessoa , Cohen Jamie A. , Kerr Cliff C. , Althouse Benjamin M. , Vasilakis Nikos , Nogueira Mauricio Lacerda
Published: April 2022

Background:

The emergence of the Brazilian variant of concern, Gamma lineage (P.1), impacted the epidemiological profile of COVID-19 cases due to its higher transmissibility rate and immune evasion ability.

Methods:

We sequenced 305 SARS-CoV-2 whole-genomes and performed phylogenetic analyses to identify introduction events and the circulating lineages. Additionally, we use epidemiological data of COVID-19 cases, severe cases, and deaths to measure the impact of vaccination coverage and mortality risk.

Results:

Here we show that Gamma introduction in São José do Rio Preto, São Paulo, Brazil, was followed by the displacement of seven circulating SARS-CoV-2 variants and a rapid increase in prevalence two months after its first detection in January 2021. Moreover, Gamma variant is associated with increased mortality risk and severity of COVID-19 cases in younger age groups, which corresponds to the unvaccinated population at the time.

Conclusions:

Our findings highlight the beneficial effects of vaccination indicated by a pronounced reduction of severe cases and deaths in immunized individuals, reinforcing the need for rapid and massive vaccination.
Theoretical predictions of phase stability for orthorhombic and hexagonal ternary MAB phases
Authors: Carlsson Adam , Rosen Johanna , Dahlqvist Martin
Published: April 2022

Screening of known and novel hypothetical ternary MAB phase structures promising for future synthesis.
A neural network potential for the IRMOF series and its application for thermal and mechanical behaviors
Authors: Tayfuroglu Omer , Kocak Abdulkadir , Zorlu Yunus
Published: April 2022

We construct a generic neural network potential (NNP) for IRMOF-n series trained by PBE-D4/def2-TZVP reference data of MOF fragments and identify bulk properties using NNP, much faster than DFT calculations.
Potential health effects of brewers’ spent grain as a functional food ingredient assessed by markers of oxidative stress and inflammation following gastro-intestinal digestion and in a cell model of the small intestine
Authors: Merten Diane , Erman Lara , Marabelli Gianluca Pierluigi , Leners Bernadette , Ney Yannick , Nasim Muhammad Jawad , Jacob Claus , Tchoumtchoua Job , Cajot Sébastien , Bohn Torsten
Published: April 2022

Brewery spent grain increased dietary fiber when incorporated into bread, together with total phenolics and antioxidant capacity. This was retained after gastro-intestinal digestion. 150 g of such a bread can supply the recommended daily 25 g of fiber.
Co-interventions withClostridium butyricumand soluble dietary fiber targeting the gut microbiota improve MAFLDviathe Acly/Nrf2/NF-κB signaling pathway
Authors: Shao Junwei , Ge Tiantian , Wei Yingliang , Zhou Yuhan , Shi Mengyuan , Liu Huiyuan , Chen Zhi , Xia Yang
Published: April 2022

Mechanisms of co-intervention with Clostridium butyricum and soluble dietary fiber to improve MAFLD.
Polyphenolic sunscreens for photoprotection
Authors: Wang Tianyou , Zhao Junyi , Yang Zhen , Xiong Lidan , Li Li , Gu Zhipeng , Li Yiwen
Published: April 2022

This paper strives to summarize the recent advances and current highlights of photoprotective polyphenolic sunscreens including structural and functional relationships, design principle, UV-protection mechanism and evaluation system.
Can perovskites be efficient photocatalysts in organic transformations?
Authors: Ketavath Ravi , Mohan Lakavathu , Sumukam Ranadeep Raj , Alsulami Qana A. , Premalatha Azmeera , Murali Banavoth
Published: April 2022

Designing and developing efficient, robust, and cost-effective photocatalysts that can support a broad scope of chemical bond formations (C–C, C–N, C–O, and C–P) is need of the hour for the emergence of next generation viable technologies.
Solvent effect on the Seebeck coefficient of Fe2+/Fe3+ hydrogel thermogalvanic cells
Authors: Liu Yang , Zhang Qi , Odunmbaku George Omololu , He Yongjie , Zheng Yujie , Chen Shanshan , Zhou Yongli , Li Jing , Li Meng , Sun Kuan
Published: April 2022

The Seebeck coefficient of Fe2+/3+ thermogalvanic cells is inversely proportional to the donor number of organic solvent additives, which cause rearrangement of the Fe2+/3+ solvent shell.
ZnO/BiFeO3 heterojunction interface modulation and rGO modification for detection of triethylamine
Authors: Bai Shouli , Tian Ke , Zhao Yingying , Feng Yongjun , Luo Ruixian , Li Dianqing , Chen Aifan
Published: April 2022

A novel 9ZBFO/rGO(1 wt%) composite exhibits excellent gas sensor performance, which is attributed to heterojunction interface modulation and rGO modification.
Method for extraction and analysis of per- and poly-fluoroalkyl substances in contaminated asphalt
Authors: Srivastava Prashant , Williams Mike , Du Jun , Navarro Divina , Kookana Rai , Douglas Grant , Bastow Trevor , Davis Greg , Kirby Jason K.
Published: April 2022

The legacy use of aqueous film-forming foam (AFFF) has led to the generation of large volumes of per- and poly-fluoroalkyl substances (PFAS)-contaminated asphalt materials, especially at airports and fire training areas.
Bacteria-responsive biopolymer-coated nanoparticles for biofilm penetration and eradication
Authors: Wang Yingying , Shukla Anita
Published: April 2022

Bacteria-responsive, hyaluronic acid and chitosan coated antibiotic loaded gelatin nanoparticles effectively penetrate and eradicate bacterial biofilms.
Cyclic voltammetry electrodynamic deposition of Co9−xMnxS8 nanosheet arrays for electrocatalytic hydrogen evolution
Authors: Gao Di , Xiao Peng , Zhang Yunhuai
Published: April 2022

Room-temperature cyclic voltammetry (CV) electrodynamic deposition is proposed for the first time to deposit Co9−xMnxS8 nanosheet arrays.
The largest Se-4f cluster incorporated polyoxometalate with high Lewis acid–base catalytic activity
Authors: Yao Meng-Ying , Liu Yu-Feng , Li Xin-Xiong , Yang Guo-Ping , Zheng Shou-Tian
Published: April 2022

The largest organic–inorganic hybrid Se-4f cluster incorporated polyoxometalate has been synthesized. It exhibits excellent Lewis acid–base catalytic activity and reusability in the gram-scale dehydration condensation reaction of hydrazines and 1,3-diketones.
High capacity ammonia adsorption in a robust metal–organic framework mediated by reversible host–guest interactions
Authors: Guo Lixia , Han Xue , Ma Yujie , Li Jiangnan , Lu Wanpeng , Li Weiyao , Lee Daniel , da Silva Ivan , Cheng Yongqiang , Rudić Svemir , Manuel Pascal , Frogley Mark D. , Ramirez-Cuesta Anibal J. , Schröder Martin , Yang Sihai
Published: April 2022

To understand the exceptional adsorption of NH3 in MFM-300(Sc), we report a full study of the mechanism of adsorption by in situ neutron diffraction, inelastic neutron scattering, synchrotron infrared microspectroscopy, and 45Sc NMR spectroscopy.
Tubular chitosan hydrogels with a tuneable lamellar structure programmed by electrical signals
Authors: Tong Jun , Yang Chen , Qi Luhe , Zhang Jingxian , Deng Hongbing , Du Yumin , Shi Xiaowen
Published: April 2022

Complex lamellar hydrogels with an arbitrary order/disorder structure: hollow chitosan hydrogels with programmable internal structure are fabricated by predesigned electrical signals.
Supramolecularly regulated artificial transmembrane signal transduction for 'ON/OFF'-switchable enzyme catalysis
Authors: Hou Jinxing , Jiang Xiaojia , Yang Feihu , Wang Liang , Yan Tengfei , Liu Shengda , Xu Jiayun , Hou Chunxi , Luo Quan , Liu Junqiu
Published: April 2022

Artificial signal transduction regulated by competitive supramolecular host–guest complexation to reversibly control an enzyme reaction inside the lipid vesicles.
Coordination polymers fabricated from Cd(NO3)2andN,N′,O-pincer-type isonicotinoylhydrazone-based polytopic ligands – an insight from experimental and theoretical investigations
Authors: Mahmoudi Ghodrat , Akbari Afkhami Farhad , Khandar Ali Akbar , White Jonathan M. , Maniukiewicz Waldemar , Babashkina Maria G. , Mitoraj Mariusz P. , Sagan Filip , Safin Damir A.
Published: April 2022

Three new Cd(ii) coordination polymers based on isonicotinohydrazide ligands (HLI,HLII) differing in the presence of a methyl unit have been obtained and extensively characterized by experimental and computational approaches.
Theoretical dynamics studies of the CH3 + HBr → CH4 + Br reaction: integral cross sections, rate constants and microscopic mechanism
Authors: Gao Delu , Xin Xin , Wang Dunyou , Szabó Péter , Lendvay György
Published: April 2022

The rate constants calculated using both quantum dynamics and the quasiclassical methods agree very well with experimental results.
Estimation of the nucleation barrier in a multicomponent system with intermolecular potential
Authors: Jiang Binfan , Lai Nien-Chu , Xia Dehong
Published: April 2022

The formation of a “critical nucleus” prior to phase change is a crucial step for new particle formation (NPF) in the atmosphere.
Vibrational properties of graphdiynes as 2D carbon materials beyond graphene
Authors: Serafini P. , Milani A. , Tommasini M. , Castiglioni C. , Proserpio D. M. , Bottani C. E. , Casari C. S.
Published: April 2022

Raman and IR spectra investigation of 2D carbon crystals belonging to the family of graphdiynes (GDYs) and having different structures is performed in this paper, focusing on how these spectra are affected by different topological features.
Chemical recycling of polyhydroxybutyrate and polylactic acid over supported Ru catalysts
Authors: Lehnertz Marcus S. , Mensah Joel B. , Palkovits Regina
Published: April 2022

As an important step towards circular value-chains for bioplastics, we report a strategy for the direct catalytic processing of two biopolyesters.
Valorization of bamboo biomass using combinatorial pretreatments
Authors: Huang Chen , Zhan Yunni , Wang Jia , Cheng Jinyuan , Meng Xianzhi , Liang Luna , Liang Fangmin , Deng Yongjun , Fang Guigan , Ragauskas Arthur J.
Published: April 2022

Current studies concerning liquid hot water pretreatment (LHWP) usually focus on cellulose saccharification or hemicellulose conversion, while the appropriate extraction and utilization of LHWP-induced lignin have not been addressed.
Electrooxidative tricyclic 6–7–6 fused-system domino assembly to allocolchicines by a removable radical strategy
Authors: Zhang Yan , Ma Chanchan , Cai Zhenzhi , Struwe Julia , Chen Shengjie , Xu Jinming , Li Shiyin , Zeng Wangyu , Ackermann Lutz
Published: April 2022

Natural allocolchicine and analogues derived thereof a tricyclic 6–7–6-system have been found as key scaffold of various biologically relevant molecules.
Radiotherapy on-chip: microfluidics for translational radiation oncology
Authors: Chermat Rodin , Ziaee Maryam , Mak David Y. , Refet-Mollof Elena , Rodier Francis , Wong Philip , Carrier Jean-François , Kamio Yuji , Gervais Thomas
Published: April 2022

Current applications of radiotherapy on-a-chip in radiation physics and radiobiology and perspectives in translational radiobiology for cancer treatment.
Autophagy targeting nanoparticles in rheumatoid arthritis and osteoarthritis
Authors: Vyawahare Akshay , Ahmad Anas , Kanika  , Ali Aneesh , Saha Puspita , Gowd Vemana , Khan Rehan
Published: April 2022

Nanotechnology has been proven to be effective several times in the treatment of various diseases.
pH-Controlled forms of 1-amino-1-hydrazino-2,2-dinitroethylene (HFOX): selective reactivity of amine and hydrazinyl groups with aldehydes or ketones
Authors: Chinnam Ajay Kumar , Staples Richard J. , Shreeve Jean’ne M.
Published: April 2022

1-Amino-1-hydrazino-2,2-dinitroethylene (HFOX) is a potential reactive intermediate for a new class of energetic materials.
Controlling coefficients of thermal expansion in thermoplastic materials: effects of zinc cyanide and ionic liquid
Authors: Egerton Savannah , Sim Claudia , Park Heon E. , Staiger Mark P. , Patil Komal M. , Cowan Matthew G.
Published: April 2022

Tuning the coefficients of thermal expansion (CTE) of polymeric materials through a combination of zinc cyanide and ionic liquid.
An energetics assessment of benzo[a]tetracene and benzo[a]pyrene as triplet–triplet annihilation emitters
Authors: Wang Xiaopeng , Marom Noa
Published: April 2022

Optical upconversion (UC) of low energy photons into high energy photons enables solar cells to harvest photons with energies below the band gap of the absorber, reducing the transmission loss.
Synthesis and characterization of polymethine dyes carrying thiobarbituric and carboxylic acid moieties
Authors: Desvals Arthur , Fortino Mariagrazia , Lefebvre Corentin , Rogier Johann , Michelin Clément , Alioui Samy , Rousset Elodie , Pedone Alfonso , Lemercier Gilles , Hoffmann Norbert
Published: April 2022

Polymethine dyes are prepared using a convenient synthesis and characterized by physicochemical and computational methods.
Magnetically separable type-II semiconductor based ZnO/MoO3 photocatalyst: a proficient system for heteroarenes arylation and rhodamine B degradation under visible light
Authors: Kaushik Bhawna , Rana Pooja , Rawat Deepti , Solanki Kanika , Yadav Sneha , Rana Pooja , Sharma R. K.
Published: April 2022

Shedding light on a magnetically retrievable ZnO/MoO3 photocatalyst that efficiently coupled diazonium substituted arenes with heteroarene substrates along with efficient degradation of toxic Rhodamine B.
Experimental and theoretical insights into thetransinfluence of organo-sulfur and -selenium ligands in 5,6-membered palladium(ii) cationic pincer complexes based on iminophosphoranes
Authors: Rodríguez-Álvarez Aurora , González-Espinoza Cristina E. , Martínez-De-León Carla Gabriela , Carrillo-Tripp Mauricio , Hô Minhhuy , Grévy Jean-Michel
Published: April 2022

Thetransinfluence of organochalcogen ancillary ligands was assessed by experimental and DFT studies in 5,6-membered SNS and SNSe Pd(ii) pincers.
Enhancing the separation efficiency of photo-induced carriers in a Bi2S3/BiOCl heterostructure by cooperative influence of oxygen vacancies and the interfacial electric field
Authors: Deng Chengming , Xu Haiming , Qin Hailan , Xia Dongsheng , Li Dongya , Yu Qilin , Chen Dahong , Zheng Yi , Wang Yujia
Published: April 2022

The outstanding photocatalytic activity of Bi2S3/BiOCl heterostructures derived from enhanced light-utilization efficiency is demonstrated.
2D MOF nanosheets as an artificial light-harvesting system with enhanced photoelectric switching performance
Authors: Liu Lin , Lu Xue-Ying , Zhang Mei-Li , Ren Yi-Xia , Wang Ji-Jiang , Yang Xiao-Gang
Published: April 2022

The assembly of 2D MOF nanosheet with coumarin 6 afforded an efficient artificial light-harvesting system, which shows a high “on–off” photocurrent ratio up to 1000.
Investigation on fluorescein derivatives with thermally activated delayed fluorescence and their applications in imaging
Authors: Lv Zhaoye , Hou Jun , Yao Junjie , Yuan Ye , Qian Yulan , Zhu Junyang , Zhao Hongjuan , Xiong Xiaoqing , Jiao Chengqi
Published: April 2022

Compounds DCF-MPYA and FL with microsecond scale lifetimes were obtained by fine tuning the substituents' structure on the basis of a fluorescein derivative with thermally activated delayed fluorescence (TADF) properties.
Beneficial roles of the AhR ligand FICZ on the regenerative potentials of BMSCs and primed cartilage templates
Authors: Huang Jing , Wang Yining , Zhou Yi
Published: April 2022

FICZ/AhR axis might be a potential target to achieve optimal bone regeneration for both BMSCs and primed cartilage templates.
A multi-color persistent luminescent phosphor β-NaYF4:RE3+ (RE = Sm, Tb, Dy, Pr) for dynamic anti-counterfeiting
Authors: Wang Bohan , Wang Zhihao , Mao Peng , Wang Yu
Published: April 2022

A dynamic anti-counterfeiting pattern was successfully designed by using the excellent luminescence characteristics of long afterglow materials under X-ray excitation.
Sustainable and highly controlled aryl couplings revealed by systematic assessment of photoactivatable linkers
Authors: Haensch Veit G. , Neuwirth Toni , Bergner Alexander , Bruhnke Jakob , Kloss Florian , Hertweck Christian
Published: April 2022

A series of photoactivatable linkers for metal-free biphenyl synthesis is presented. Alternative substrates for the photosplicing reaction can reduce toxic byproducts and problematic starting materials.
NiO–Ti nanocomposites for contact electrification and energy harvesting: experimental and DFT+U studies
Authors: Padhan Aneeta Manjari , Hajra Sugato , Kumar Jagadish , Sahu Manisha , Nayak Sanjib , Khanbareh Hamideh , Kim Hoe Joon , Alagarsamy Perumal
Published: April 2022

Triboelectric nanogenerators (TENGs) have recently attracted extensive attention from academia and industry as a promising approach for energy harvesting.
A hierarchical thermal interface material based on a double self-assembly technique enables efficient output power via solar thermoelectric conversion
Authors: Gao Yueyang , Zhang Minghang , Cui Yexiang , Bao Di , Xu Fei , Shen Xiaosong , Zhu Yanji , Wang Huaiyuan
Published: April 2022

This study exhibits potential prospects in thermal management fields and promising alternatives for the thermal harvesting of renewable energy.
Correction: High-performance dual-ion Zn batteries enabled by a polyzwitterionic hydrogel electrolyte with regulated anion/cation transport and suppressed Zn dendrite growth
Authors: Li Longwei , Zhang Lanshuang , Guo Wenbin , Chang Caiyun , Wang Jing , Cong Zifeng , Pu Xiong
Published: April 2022

Correction for ‘High-performance dual-ion Zn batteries enabled by a polyzwitterionic hydrogel electrolyte with regulated anion/cation transport and suppressed Zn dendrite growth’ by Longwei Li et al., J. Mater. Chem. A, 2021, 9, 24325–24335, https://doi.org/10.1039/D1TA08127F.
Raman and scanning probe microscopy for differentiating surface imprints of E. coli and B. cereus
Authors: Bräuer Birgit , Werner Martin , Baurecht Dieter , Lieberzeit Peter A.
Published: April 2022

Nanomechanical AFM and Raman-Microscopy data give evidence that surface imprinting of bacteria leads to chemical differences in cavities caused by different species. This experimentally corroborates a fundamental assumption of molecular imprinting.
Tetraphenylethylene-based Eu3+-metallopolymers with aggregation-enhanced white emission for self-calibrating temperature sensing and white light-emitting diodes (WLEDs)
Authors: Huang Yujuan , Feng Weixu , Zhou Zhanpeng , Zheng Huize , Zhao Yan , Yan Hongxia , Lü Xingqiang
Published: April 2022

High-efficiency white light emission has been achieved for tetraphenylethylene-based Eu3+-metallopolymers, which also exhibited great potential for applications in ratiomeric temperature sensing and white light emitting diodes.
Theoretical and experimental investigation of AC and DC arc propagation on polluted insulators surface
Authors: Dong Bingbing , Wu Ben , Wang Zhizheng , Jiang Xingliang
Published: April 2022

To acquire new knowledge of pollution flashover mechanism of insulators, the mechanical characteristics of local arc propagation on suspension insulators surface during AC and DC pollution flashover are analyzed in this paper. The results indicate that the propagation of local arc mainly depends on the electrostatic force and thermal buoyancy. The thermal buoyancy plays a leading role in the bigger arc current, resulting in the obvious phenomenon of arc wandering. Moreover, the effect of thermal buoyancy on AC arc is less than that on DC arc at the same arc current. DC arc wandering is more significant than that of AC. With the decrease in air pressure (the increase in altitude height), the effect of thermal buoyancy rises. As a result, it will cause severe arc‐levitating at high altitudes, making the flashover distance of insulators less than its creepage distance. Therefore, the arc‐levitating is one of the key factors for the decrease in flashover voltage of polluted insulators in high‐altitude regions.
Multi‐step implicit Adams predictor‐corrector network for fire detection
Authors: Deng Zhen , Hu Shuhao , Yin Shibai , Wang Yibin , Basu Anup , Cheng Irene
Published: April 2022

Fire detection methods based on the Convolutional Neural Networks (CNN) have advantages of high accuracy, wide coverage and robustness, receiving significant attention from researchers. Among CNN‐based methods, ResNet has achieved better performance than other CNN frameworks in fire detection system, since it uses stacked residual blocks to enlarge the receptive field to overcome the vanishing gradient problem with residual learning. The merits of ResNet can be attributed to the similarity between ResNet and the single‐step explicit solver for Ordinary Differential Equations (ODEs), for example, the Euler method. Motivated by the theory of numerical ODE that a multi‐step implicit solver has higher accuracy than a single‐step explicit solver, the Multi‐step Implicit Adams predictor‐corrector (MIAPC) network for fire detection is proposed. The MIAPC method is first mapped to a corresponding predictor‐corrector Adams block which achieves higher accuracy than a single‐step explicit solver. Then, Adaptive Feature Fusion (AFF) and the Spatial Attention Layer (SAL) are utilized to extract hierarchical features from stacked predictor‐corrector Adams blocks, forming the corresponding Adams module. Finally, the 4 Adams modules which are made of 4, 6, 8, 10 predictor‐corrector Adams blocks and followed by AFF and SAL form the crucial ODE‐based approximation part in the proposed network. By adding a simple feature extraction and detection in front of and after the ODE‐based approximation part, the MIAPC network is built. Experiments demonstrate that the method achieves 87% accuracy in the challenging test dataset, outperforming existing methods by at least 6%. Besides, the 5.3M model size with inference speed of 4.7 frames/second in CPU and 65.7 frames/second in GPU enables the proposed method to be used in practical applications.
Coherent processing for randomized stepped‐frequency radar in multi‐target scenario
Authors: Liu Shuai , Cao Yunhe , Yeo Tat‐Soon , Wang Fengfei , Zhao Yuchao
Published: April 2022

Randomized stepped‐frequency (RSF) radar has the potential of realizing joint high‐resolution range‐Doppler estimation. However, estimating multiple targets' two‐dimensional parameters at high efficiency based on RSF waveforms is still a difficult issue. In this study, a novel algorithm, which estimates multiple targets' velocities by using different frequencies pulses and then generates their high‐range‐resolution profiles (HRRPs), is proposed for RSF radar. In the velocities estimation, by setting a certain difference‐frequency parameter, a set of signals with constant range‐phase terms and changing velocity‐phase terms is constructed and then used to generate a new generalized Doppler spectrum called the difference‐frequency Doppler spectrum (DFDS). To suppress rising noise floors caused by sidelobes and cross‐terms in the DFDS, DFDSs corresponding to different difference‐frequency parameters are non‐coherently integrated to obtain a so‐called accumulated DFDS. From the accumulated DFDS, targets are detected and their velocities are estimated. In the HRRPs generation, a special dictionary matrix is structured by using the estimated velocities, and each target HRRP, without interference from other targets, is generated via the compressed sensing (CS) technique. The proposed algorithm avoids huge computation burden by separately performing Doppler and range process, and guarantees the performance in a multi‐target scenario via the noise floors suppression and CS.
Propriétés des terrains briovériens du bassin rennais
Authors: Merrien-Soukatchoff Véronique , Rangeard Damien
Published: April 2022

Le bassin rennais est majoritairement constitué de terrains briovériens, schisteux, fracturés et présentant des degrés d’altération variables. Le Briovérienpeut être recouvert par des formations superficielles et quelques intrusions magmatiques sont injectées dans les terrains plus anciens. Les matériaux rencontrés ont une faible résistance mécanique qui les classe en SIRT (Sols indurés et Roches tendres). Pendant plusieurs années, des essais ont été réalisés sur les matériaux de l’agglomération rennaise, principalement datés du Briovérien, pour définir leurs caractéristiques et mieux comprendre le comportement des ouvrages géotechniques réalisés dans le sous-sol rennais. L’excavation de la ligne b dumétro anotammentpermis d’avoir des échantillons de l’Ouest à l’Est de la ville de Rennes. Compte tenu du comportement intermédiaire entre le sol et la roche des terrains, des procédures spécifiques d’essais sur la matrice rocheuse et les discontinuités ont été développées. La matrice rocheuse, anisotrope, a été caractérisée par des mesures de vitesse d’ondes et des essais de résistance à la compression. Cependant compte tenu de l’impossibilité de carotter le matériau, les essais ont été réalisés sur des blocs parallélépipédiques taillés à la main. En complément, pour évaluer le caractère « friable » de ces SIRT, la résistance à l’usure a été caractérisée àpartir d’essais debroyabilité etmicro-Deval modifiés. L’ensemble des essais montre des variations fonction du faciès, mais aussi une forte influence de l’altération et de la teneur en eau. Les discontinuités ont été testées avec une boîte de Casagrande modifiée. Ces essais ont aussi montré la forte influence du type de matériau (siltites, grès grossier à fin…) et du degré d’humidité des joints sur les caractéristiques de cisaillement. Des différences de comportement entre faciès géologiques ont donc été mises en évidence. L’histoire géologique et, en particulier, les alternances de progradation et de rétrogradation lors de la sédimentation au Briovérien, conditionne les propriétés de la matrice rocheuse, des discontinuités et donc du massif rocheux.
Analyses et modélisations sur les argiles plastiques du Sparnacien du Bassin parisien
Authors: Zhang Yi , Commend Stéphane , Groslambert Marc
Published: April 2022

Les argiles plastiques d’âge Sparnacien (Eocène inférieur) présentent un enjeu géotechnique fort pour le projet Grand Paris Express, un des plus grands projets du métro en cours de construction en Europe. Ces Argiles plastiques sont imperméables, normalement consolidées ou surconsolidées, et présentent un potentiel de gonflement. Le mécanisme de gonflement des Argiles plastiques est complexe car il dépend de ses caractéristiques physiques et chimiques, ainsi que de ses états mécaniques et hydriques. Dans cet article, nous présentons d’abord les analyses des retours d’expériences sur les Argiles plastiques, ainsi que les paramètres géotechniques et les lois de comportement utilisés dans ces REX. Ensuite, nous présentons les différentes méthodes de modélisation des Argiles plastiques, à savoir la solution analytique et empirique, la méthode aux éléments finis semi-probabiliste et l’approche probabiliste. De plus, les applications numériques aux différents types d’ouvrages sont également réalisées, à savoir puits, parois moulées et tunnels. Les résultats de ces calculs ont été comparés aux mesures d’auscultations, qui permettent de vérifier les résultats des simulations numériques. À la fin, une analyse inverse à l’aide de la méthode d’inférence Bayésienne a été effectuée pour préciser la prédiction du gonflement des Argiles plastiques.
Long-term tracking of Arctic ice with acoustic observations
Authors: Thompson Avery
Published: April 2022

Remote hydrophone allows for real-time monitoring of environmental variables in inhospitable conditions.
Quiet or loud? Hand position matters when it comes to voice directivity
Authors: Piccone Ashley
Published: April 2022

First systematic study demonstrates hand postures affect voice radiation more than differences between phonemes
Ammonium salts enhance heterogeneous ice nucleation through entropy increase
Authors: Green Leigh Ann
Published: April 2022

Formation of ice clusters results from the charged or polar surface of ice nucleators
Even-order harmonic generation from nonlinear Thomson backscatter in a tightly focused Gaussian laser pulse
Authors: Hong Xue-Ren , Li Ya-Nan , Wei Dou , Tang Rong-An , Sun Jian-An , Duan Wen-Shan
Published: April 2022

The electron dynamics and the Thomson backscattering spectra for an electron accelerating in a tightly focused Gaussian laser pulse are first investigated in detail. It is found that for a tightly focused Gaussian laser pulse, the ponderomotive force introduced due to the non-uniform intensity distribution of the laser pulse has the tendency to push out the electron from the laser pulse, which leads to the trajectory symmetry-breaking of the electron and then the generation of the even-order harmonics at the same time. Further, for the tightly focused Gaussian laser pulse, changes in several laser parameters, such as the increase of the laser peak amplitude, lengthening of the pulse width, and decrease of the beam waist, lead earlier to the relative ejected position of the electron to the laser pulse, which causes the more obvious trajectory symmetry-breaking of the electron, and then the more intensive peak intensity of the even-order harmonics. It is different from the well-known results of the plane waves and the Gaussian laser pulse with uniform transverse intensity distribution and provides a possible way for the generation of the even-order harmonics in nonlinear Thomson backscattering.
How to maximize the bandwidth without increasing the noise in op-amp-based transimpedance amplifiers using positive feedback
Authors: Su Bo , Yang Xue , Cui Hailin , Jones David R.
Published: April 2022

The bandwidth of very high gain (≥100 MV/A) transimpedance amplifiers is restricted to below 100 kHz, unless measures are employed to mitigate the effect of circuit parasitic capacitances. Current approaches involve significantly increased circuit complexity and component count. They may suffer unwanted noise pickup or destructive capacitive coupling to ground, the latter restricting the available bandwidth. We demonstrate that combining a positive feedback circuit with a low-pass filter network extends the bandwidth of a transimpedance amplifier out to the limit of gain peaking (>1 MHz) without increasing the noise signal. The circuit uses a single inverting amplifier and very large feedback-resistance to provide a canceling parasitic-capacitance positive feedback signal. This can negate both the negative feedback-resistor parasitic-capacitance and the input/output pin parasitic-capacitance of the transimpedance amplifier. The circuit solves the problem of destructive distributed-capacitive coupling to ground along the feedback resistor.
Intercalation of metal–aluminum layered double hydroxides with anionic surfactants: Experimental and density functional theory studies
Authors: David Emem , Anyama Chinyere Ayi , Ayi Ayi A. , Louis Hitler , Oseghale Charles O.
Published: April 2022

Metal–aluminum layered double hydroxides (LDHs) intercalated with bis(2-ethylhexyl)sulfosuccinate (EHS) and dodecyl sulfate (SDS) anions, formulated as EHS-MgAl-LDH 1, SDS-MgAl-LDH 2, EHS-CaAl-LDH 3, and SDS-CaAl-LDH 4, were synthesized using the co-precipitation method. The compounds were characterized using Fourier transform infrared spectroscopy, x-ray diffraction, transmission electron microscopy, scanning electron microscopy, and thermogravimetric analysis. The textural properties were studied using the Brunauer–Emmett–Teller method. The density functional theory method was used to perform computational calculations of the surfactants (EHS and SDS) and the Pb(II)-surfactant bonds (EHS-Pb and SDS-Pb) in the layered double hydroxides. Natural bond orbital (NBO) calculation for the investigation of the stabilization energy and charge transfer performed on the compounds showed significant donor–acceptor NBO interactions between π^*C7–O8 → σ^*C7–O8, LP(3)O13 → π^*C12–O14, LP(3)O3 → σ^*S1–O5, and π^*S1–O3→ σ^*S1–O2 natural bond orbitals, having second-order stabilization energies of 285.84, 92.84, 30.78, and 447.27 kcal/mol, respectively. The observed highest and least perturbation energies within the compounds are observed to occur between LP(3)O13 → π^*C12–O14 and π^*S1–O3 → σ^*S1–O2 interacting orbitals with stabilization energies of 92.84 and 447.27 kcal/mol, respectively. The HOMO–LUMO energy gap results showed an increase in the energy values as the surfactant interacts with the Pb(II) ions. This increase in the energy gap is responsible for the stability of the surfactant–metal complexes and demonstrates the potential of the surfactant for the removal of the heavy metal ions in solution. The compounds were used as adsorbents for the removal of lead(II) ions from wastewater.
Composition dependent electrochemical properties of earth-abundant ternary nitride anodes
Authors: Tellekamp M. Brooks , Osella Anna , Heinselman Karen N. , Tamboli Adele C. , Ban Chunmei
Published: April 2022

Growing energy storage demands on lithium-ion batteries necessitate exploration of new electrochemical materials as next-generation battery electrode materials. In this work, we investigate the previously unexplored electrochemical properties of earth-abundant and tunable Zn1−xSn1+xN2 (x = −0.4 to x = 0.4) thin films, which show high electrical conductivity and high gravimetric capacity for Li insertion. Enhanced cycling performance is achieved compared to previously published end-members Zn3N2 and Sn3N4, showing decreased irreversible loss and increased total capacity and cycle stability. The average reversible capacity observed is >1050 mAh/g for all compositions and 1220 mAh/g for Zn-poor (x = 0.2) films. Extremely Zn-rich films (x = −0.4) show improved adhesion; however, Zn-rich films undergo a phase transformation on the first cycle. Zn-poor and stoichiometric films do not exhibit significant phase transformations which often plague nitride materials and show no required overpotential at the 0.5 V plateau. Cation composition x is explored as a mechanism for tuning relevant mechanical and electrochemical properties, such as capacity, overpotential, phase transformation, electrical conductivity, and adhesion. The lithiation/delithiation experiments confirm the reversible electrochemical reactions. Without any binding additives, the as-deposited electrodes delaminate resulting in fast capacity degradation. We demonstrate the mechanical nature of this degradation through decreased electrode thinning, resulting in cells with improved cycling stability due to increased mechanical stability. Combining composition and electrochemical analysis, this work demonstrates for the first time composition dependent electrochemical properties for the ternary Zn1−xSn1+xN2 and proposes earth-abundant ternary nitride anodes for increased reversible capacity and cycling stability.
Determining the atom number from detection noise in a one-dimensional optical lattice clock
Authors: Lu Xiaotong , Xia Jingjing , Lu Benquan , Wang Yebing , Wang Tao , Chang Hong
Published: April 2022

In this paper, we demonstrate in situ synchronous frequency comparison between distinct regions in a one-dimensional optical lattice. The synchronous comparison instability is well below the Dick limit and agrees with the limit induced by atomic detection noise. The absolute atom number is extracted from the synchronous comparison instability with an uncertainty below 3%. Surpassing the performance of absorption imaging, this method provides a way to directly and precisely determine the absolute atom number from detection noise. Taking advantage of the inhomogeneous density distribution over the whole lattice, the density shift can also be conveniently measured by this synchronous frequency comparison method. Inconsistent with the expectation of the linear relationship between density shift and atom number difference, nonlinearity is observed, indicating that the assumption of an identical density shift coefficient over the whole lattice is not always safe.
Coupled metronomes on a moving platform with Coulomb friction
Authors: Goldsztein Guillermo H. , English Lars Q. , Behta Emma , Finder Hillel , Nadeau Alice N. , Strogatz Steven H.
Published: April 2022

Using a combination of theory, experiment, and simulation, we revisit the dynamics of two coupled metronomes on a moving platform. Our experiments show that the platform’s motion is damped by a dry friction force of Coulomb type, not the viscous linear friction force that has often been assumed in the past. Prompted by this result, we develop a new mathematical model that builds on previously introduced models but departs from them in its treatment of friction on the platform. We analyze the model by a two-timescale analysis and derive the slow-flow equations that determine its long-term dynamics. The derivation of the slow flow is challenging due to the stick-slip motion of the platform in some parameter regimes. Simulations of the slow flow reveal various kinds of long-term behavior including in-phase and antiphase synchronization of identical metronomes, phase locking and phase drift of non-identical metronomes, and metronome suppression and death. In these latter two states, one or both of the metronomes come to swing at such low amplitude that they no longer engage their escapement mechanisms. We find good agreement between our theory, simulations, and experiments, but stress that our exploration is far from exhaustive. Indeed, much still remains to be learned about the dynamics of coupled metronomes, despite their simplicity and familiarity.
Numerical study on the influence of pre-swirl angle on internal flow characteristics of centrifugal pumps
Authors: Wang Y. , Xu W. , Yin H. , Zhang Y. , Dou H.-S.
Published: April 2022

The effect of inlet pre-swirl on the performance of a centrifugal pump is studied by numerical simulation. The governing equations are Navier–Stokes equations and the shear stress transport k–ω turbulence model. The numerical results show that the optimal operating point moves from the low flow region to the high flow region as the pre-swirl angle shifts from positive to negative. It is found by contours of Omega–Liutex that the positive pre-swirl angle is able to weaken the vortex on the blade suction and reduce the energy dissipation. On both the 0.5Q0 and 1.2Q0 operating conditions, the proportion of entropy production loss in the impeller and volute is about 60% and 30%, respectively. As the pre-swirl angle changes from negative to positive, the entropy production loss in the inlet and outlet pipes increases slowly, and the entropy production loss in the volute and impeller shows a decreasing trend and the peak area of entropy loss moves toward the outlet. Under the four pre-swirl angles, the main frequency is always the passing frequency of the blade. The pre-swirl angle affects the pressure fluctuation at the main frequency but has little effect at the secondary frequency. The change in velocity pulsation amplitude in the impeller in the positive pre-swirl angle is smaller than that in the negative pre-swirl angle. As a result, for the positive pre-swirl angle, the turbulent kinetic energy density in the impeller is low, and the energy loss is low, compared with negative pre-swirl. Under the low flow condition (0.5Q0), the change in velocity pulsation amplitude in the inertial range of the energy spectrum under negative pre-swirl is greater than that under positive pre-swirl.
Polymorphic selectivity in crystal nucleation
Authors: Gui Yue , Huang Chengbin , Shi Chenyang , Stelzer Torsten , Zhang Geoff G. Z. , Yu Lian
Published: April 2022

Crystal nucleation rates have been measured in the supercooled melts of two richly polymorphic glass-forming liquids: ROY and nifedipine (NIF). ROY or 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile is known for its crystals of red, orange, and yellow colors and many polymorphs of solved structures (12). Of the many polymorphs, ON (orange needles) nucleates the fastest with the runner up (Y04) trailing by a factor of 103 when compared under the same mobility-limited condition, while the other unobserved polymorphs are slower yet by at least 5 orders of magnitude. Similarly, of the six polymorphs of NIF, γ′ nucleates the fastest, β′ is slower by a factor of 10, and the rest are slower yet by at least 5 decades. In both systems, the faster-nucleating polymorphs are not built from the lowest-energy conformers, while they tend to have higher energies and lower densities and thus greater similarity to the liquid phase by these measures. The temperature ranges of this study covered the glass transition temperature Tg of each system, and we find no evidence that the nucleation rate is sensitive to the passage of Tg. At the lowest temperatures investigated, the rates of nucleation and growth are proportional to each other, indicating that a similar kinetic barrier controls both processes. The classical nucleation theory provides an accurate description of the observed nucleation rates if the crystal growth rate is used to describe the kinetic barrier for nucleation. The quantitative rates of both nucleation and growth for the competing polymorphs enable prediction of the overall rate of crystallization and its polymorphic outcome.
Improving the start-up characteristics of the rubidium atomic clock
Authors: Guo Yonggang , Zhu Lili , Wang Shiwei , Zhang Jun , Shi Fucheng , Zhang Jinhai , Wang Jianxiang , Li Wenxin , Liu Zhidong
Published: April 2022

Considering the importance of start-up characteristics of the rubidium atomic clock in engineering applications, the objective of this paper is to optimize the start-up characteristics of the rubidium atomic clock by studying the theory of the rubidium atomic frequency standards, especially the light pumping process, and the effect of light intensity on frequency accuracy. Our analysis demonstrated that frequency accuracy is proportional to the light intensity, and hence, we propose a method for actively optimizing the start-up characteristics of the rubidium atomic clock by utilizing the fluctuations in light intensity. Additionally, some related experiments using the proposed method indicate that the light intensity–frequency coefficient of the rubidium atomic clock is improved from 1.84 × 10−9 to 4.21 × 10−10 V−1 within 30 min after the rubidium atomic clock is locked, and also, the lockout time is less than 5 min with a wide working temperature range (0–50 °C), indicating a significant improvement in the start-up characteristics of the rubidium atomic clock.
Nanoscale thermal imaging of VO2 via Poole–Frenkel conduction
Authors: Spitzig Alyson , Pivonka Adam , Frenzel Alex , Kim Jeehoon , Ko Changhyun , Zhou You , Hudson Eric , Ramanathan Shriram , Hoffman Jennifer E. , Hoffman Jason D.
Published: April 2022

We present a method for nanoscale thermal imaging of insulating thin films using atomic force microscopy (AFM), and we demonstrate its utility on VO2. We sweep the applied voltage V to a conducting AFM tip in contact mode and measure the local current I through the film. By fitting the IV curves to a Poole–Frenkel conduction model at low V, we calculate the local temperature with spatial resolution better than 50 nm using only fundamental constants and known film properties. Our thermometry technique enables local temperature measurement of any insulating film dominated by the Poole–Frenkel conduction mechanism and can be extended to insulators that display other conduction mechanisms.
The He–H3+ complex. I. Vibration-rotation-tunneling states and transition probabilities
Authors: Harding Michael E. , Lipparini Filippo , Gauss Jürgen , Gerlich Dieter , Schlemmer Stephan , van der Avoird Ad
Published: April 2022

With a He–H3+ interaction potential obtained from advanced electronic structure calculations, we computed the vibration-rotation-tunneling (VRT) states of this complex for total angular momenta J from 0 to 9, both for the vibrational ground state and for the twofold degenerate v2 = 1 excited state of H3+. The potential has three equivalent global minima with depth De = 455.3 cm−1 for He in the plane of H3+, three equatorial saddle points that separate these minima with barriers of 159.5 cm−1, and two axial saddle points with energies of 243.1 cm−1 above the minima. The dissociation energies calculated for the complexes of He with ortho-H3+ (oH3+) and para-H3+ (pH3+) are D0 = 234.5 and 236.3 cm−1, respectively. Wave function plots of the VRT states show that they may be characterized as weakly hindered internal rotor states, delocalized over the three minima in the potential and with considerable amplitude at the barriers. Most of them are dominated by the jk = 10 and 11 rotational ground states of oH3+ and pH3+, with the intermolecular stretching mode excited up to v = 4 inclusive. However, we also found excited internal rotor states: 33 in He–oH3+, and 22 and 21 in He–pH3+. The VRT levels and wave functions were used to calculate the frequencies and line strengths of all allowed v2 = 0 → 1 rovibrational transitions in the complex. Theoretical spectra generated with these results are compared with the experimental spectra in Paper II [Salomon et al., J. Chem. Phys. 156, 144308 (2022)] and are extremely helpful in assigning these spectra. This comparison shows that the theoretical energy levels and spectra agree very well with the measured ones, which confirms the high accuracy of our ab initio He–H3+ interaction potential and of the ensuing calculations of the VRT states.