bluuebunny/crossref_metadata_2025 huggingface dataset:
Delegierbarkeit von eigenständigen heilkundlichen Tätigkeiten an
Notfallsanitäterinnen und Notfallsanitäter: Ergebnisse einer Umfrage unter den
ÄLRD Bayerns
Authors: Dittmar Michael S. , Kraus Marina , Ebersperger Christian , Bayeff-Filloff Michael
Published: April 2022

Ziel der Studie Notfallsanitäterinnen und Notfallsanitäter (NotSan) können
unter anderem aufgrund einer Delegation durch den Ärztlichen Leiter
Rettungsdienst (ÄLRD) eigenständig heilkundlich tätig werden. Welche
heilkundlichen Maßnahmen hierfür geeignet sind, wurde in einer Umfrage unter
allen bayerischen ÄLRD, den Ärztlichen Bezirksbeauftragten (ÄBRD) sowie dem
Landesbeauftragten (ÄLBRD) erhoben.

Methodik Mittels Fragebögen wurden 43 heilkundliche Maßnahmen bezüglich
ihrer Delegierbarkeit nach §4 Abs. 2 Nr. 2c NotSanG (ÄLRD-Delegation)
bewertet.

Ergebnisse Zwölf Maßnahmen wurden im Konsens als delegierbar (davon 4 mit
starkem Konsens), 10 als nicht delegierbar eingestuft (5 mit starkem Konsens).
Von den bereits in Bayern delegierten Tätigkeiten erreichte die i. v.
Medikamentengabe knapp keine Zustimmung.

Schlussfolgerung Es liegt erstmals ein konsentierter Katalog an durch ÄLRD
delegierbaren heilkundlichen Tätigkeiten durch NotSan vor. Die Delegierbarkeit
stellt eine notwendige, aber keine hinreichende Bedingung zur Berücksichtigung
der betreffenden Maßnahmen in Delegationsvorgaben dar.
Unprecedented Rearrangement of β-Difluoroboryloxy Ethers: A Route to C-2 Alkyl-chromenones
Authors: Sarkar Debayan , Sahoo Sushree Ranjan , Somu Prathap , Paul Subhankar , Lönnecke Peter
Published: April 2022

The addition of boron trifluoride etherate (BF3·OEt2) to allenic ketones has led to the isolation of the isolated boron difluoride enolates. The single-crystal structure of boron enolate has been solved. The unprecedented C1–C10 migration of (Z)-β-difluoroboryloxy ether derivatives is observed to deliver rearranged phenol derivatives which are functionalized to C-2 alkyl-chromenones. Interestingly the isolated boron enolates have exhibited significant anticancer properties.
Recent Applications of Quinolinium Salts in the Synthesis of Annulated Heterocycles
Authors: Das Suven
Published: April 2022

Quinoline derivatives are frequently found in natural products and biologically active compounds; however, construction of quinoline fused polyheterocycles is a challenging goal in synthetic organic chemistry. In this regard, quinolinium salts meet the demand to a great level, as they can be synthesized readily and employed effectively for rapid construction of the condensed heterocyclic core. The present review focuses on recent (2015–2021) applications of different quinolinium salts, which react with suitable partners to access diverse annulated products. Most of the reactions discussed here involve easily available starting materials, are operationally simple, offer high atom-efficiency, and are environmentally benign. Mechanistic aspects of representative transformations have also been highlighted to better understand the reaction pathways.

1 Introduction

2 Annulation Involving N-Alkyl Quinolinium Salts

2.1 Reaction with Alkenes

2.2 Reaction with Alkynes/Arynes

2.3 Reaction with Phenolic Compounds

2.4 Reaction with Cyclic/Acyclic Diketones

2.5 Reaction with Amines/Cyclic Amines

2.6 Reaction with Enamines

2.7 Reaction with Isocyanoacetates

2.8 Reaction with Cyclopropanes

2.9 Ring Expansion Reactions

3 Annulation Involving Quinolinium Zwitterionic Tosylates

3.1 Reaction with Alkynes/Arynes

3.2 Reaction with Allenes/Ketenes

3.3 Reaction with Aldehyde-Amino Acid (Azomethine Ylide)

3.4 Reaction with Sulfonium Salts

3.5 Reaction with Diazoacetate

4 Annulation Involving Quinolinium Zwitterionic Thiolates

4.1 Reaction with Sulfonium Salts

4.2 Reaction with Sulfenes

4.3 Reaction with Arynes

5 Annulation Involving Quinoline N-Oxides

5.1 Reaction with Diynes and Ynones

5.2 Lactonization Involving Acrylate

6 Annulation Involving N-Iminoquinolinium Salts

6.1 Reaction with Allenoates

6.2 Reaction with Hydroxymethylallyl Carbonate

7 Miscellaneous Cyclizations

8 Conclusions
Selective N2-Alkylation of 1H-Indazoles and 1H-Azaindazoles
Authors: Londregan Allyn T. , Clemens Jennifer , Bell Emily L.
Published: April 2022

A general and selective procedure for the N2-alkylation of 1H-indazoles and 1H-azaindazoles is presented. Promoted by either trifluoromethanesulfonic acid or copper(II) triflate, diverse 1H-indazoles/azaindazoles are selectively alkylated with varied primary, secondary, and tertiary alkyl 2,2,2-trichloroacetimidates at the N2-nitrogen to afford the corresponding 2-alkyl-2H-indazoles/azaindazoles. Forty-one examples are included along with a discussion of reaction optimization, scope, and mechanism.
Incidence and Patterns of Liver Cancers in Sri Lanka from 2001 to 2010: Analysis of National Cancer Registry Data
Authors: Jayarajah Umesh , Udayanga Viraj , Fernando Ashan , Samarasekera Dharmabandhu N. , Seneviratne Sanjeewa
Published: April 2022

Objectives Varying trends in the incidence of liver cancer have been observed in many Asian countries. We conducted this study to examine trends in liver cancer incidence and histological patterns in Sri Lanka.

Materials and Methods All newly diagnosed patients with liver cancer included in Sri Lanka National Cancer Registry during 2001 to 2010 were analyzed.

Statistical Analysis Joinpoint regression analysis was performed. A p-value of less than 0.05 was considered statistically significant.

Results Overall, 1,482 (male:female = 2.7:1; mean age = 57.5 years) liver cancers were analyzed. Majority were hepatocellular carcinomas (n = 1,169; 78.9%), followed by intrahepatic cholangiocarcinomas (n = 100; 6.75%). Highest incidence of liver cancer was observed in 70–74-year age group (5.1/100,000). Overall, the World Health Organization age-standardized rate (ASR) has increased during 2001 to 2004, from 0.6/100,000 (95% confidence interval [CI] = 0.48–0.72) to 1.0/100,000 (95% CI = 0.85–1.15), with an estimated annual percentage change (EAPC) of 17.8 (95% CI = 5.0–46.2); p > 0.05. From 2004 to 2010, a gradual decline in the incidence was observed. ASR in 2010 was 0.96 (95% CI = 0.81–1.1), with an EAPC of –0.9 (95% CI = –6.7 to 5.4); p > 0.05. Similar patterns of incidence change were observed in both genders.

Conclusions Overall, the incidence of liver cancer appears to be steadily declining in Sri Lanka. Similar patterns of incidence change were observed in both genders. The actual decline is likely to be greater as it is likely that diagnostic scrutiny and reporting would have improved during the study period.
O ângulo de Baumann: Uma análise da teoria à prática
Authors: Generoso Talissa O. , Pacifico Junior Giovani M. , Barcelos Filipe M. , Blumetti Francesco C. , Braga Susana R. , Ramalho Junior Amâncio
Published: April 2022

Objetivo Analisar como o ângulo de Baumann (AB) é afetado por inclinações radiográficas inadequadas.

Métodos Estudo realizado a partir de radiografias do úmero distal de crianças de 3 a 10 anos. Foram comparadas as aferições do AB realizadas por cinco observadores, e cada radiografia foi avaliada quanto à sua qualidade em “adequada” ou “inadequada”. A correlação entre a qualidade radiográfica e a normalidade dos ângulos foi avaliada.

Resultados Amostra composta por 141 pacientes, 44% entre 3 e 6 anos e 56% entre 7 e 10. Observamos AB entre 52,01 e 89,82 graus, tendo cerca de 16% das medidas fora dos limites de normalidade da literatura. Um total de 33,3% das radiografias avaliadas foram classificadas como “inadequadas”. Sobre as medidas do AB fora do parâmetro da normalidade, observamos que sua proporção foi maior entre as imagens com qualidade radiográfica inadequada (31,1% vs. 6,2%), tendo essa diferença se mostrado significativa (p < 0,001).

Conclusões O AB é uma medida muito variável e, isoladamente, pouco confiável para a avaliação de deformidades angulares do cotovelo pediátrico, tendo a qualidade radiográfica se mostrado um fator causal importante dessa variabilidade.
Antropometria sacropélvica na população portuguesa e sua importância na colocação de parafusos em cirurgias da coluna vertebral: Análise retrospectiva de um único centro
Authors: Pereira Catarina da Silva , Maçães André Oliveira , Lemos Carolina Luisa , Rodrigues-Pinto Ricardo
Published: April 2022

Objetivo O objetivo deste estudo foi avaliar a antropometria sacropélvica da população portuguesa por meio de exames de tomografia computadorizada (TC).

Métodos Quarenta TCs pélvicas foram analisadas para determinação do comprimento e ângulo das trajetórias definidas dos parafusos, como trajetória anterior (S1A), anterolateral (S1AL) e anteromedial (S1AM) do parafuso no pedículo de S1, trajetória anterolateral (S2AL) e anteromedial (S2AM) do parafuso no pedículo de S2 e trajetória ilíaca alar (S2AI), ilíaca e sacroilíaca (SI) do parafuso em S2. Comparações entre sexos também foram realizadas.

Resultados O comprimento médio da trajetória S1A foi de 30,80 mm. O comprimento médio e o ângulo lateral de S1AL foram de 36,48 mm e 33,13°, respectivamente, e de S1AM, 46,23 mm e 33,21°. O comprimento médio e o ângulo lateral de S2AL foram de 28,66 mm e 26,52° e, de S2AM, 29,99 mm e 33,61°. O comprimento médio da trajetória ilíaca alar e os ângulos lateral e caudal do parafuso em S2 foram de 125,84 mm, 36,78° e 28,66°, respectivamente. O comprimento médio da trajetória ilíaca e os ângulos lateral e caudal foram 136,73 mm, 23,86° e 24,01°, respectivamente. O comprimento da trajetória sacroilíaca foi de 75,50 mm. O comprimento dos parafusos foi maior em homens do que em mulheres, à exceção dos parafusos S1A e SI, que não apresentaram diferenças entre os sexos.

Conclusão Este estudo descreve as especificações anatômicas sacropélvicas. Esses detalhes morfométricos definidos devem ser considerados durante os procedimentos cirúrgicos.
Demonstration of plasma mirror capability for the OMEGA Extended Performance laser system
Authors: Scott G. G. , Mariscal D. A. , Canning D. , Heeter R. F. , Krieger M. , Wallace R. J. , McGuffey C. , Peebles J. L. , Simpson R. A. , Stoeckl C. , Ma T.
Published: April 2022

A plasma mirror platform was developed for the OMEGA-EP facility to redirect beams, thus enabling more flexible experimental configurations as well as a platform that can be used in the future to improve laser contrast. The plasma mirror reflected a short pulse focusing beam at 22.5° angle of incidence onto a 12.5 μm thick Cu foil, generating Bremsstrahlung and kα x rays, and accelerating ions and relativistic electrons. By measuring these secondary sources, the plasma mirror key performance metrics of integrated reflectivity and optical quality are inferred. It is shown that for a 5 ± 2 ps, 310 J laser pulse, the plasma mirror integrated reflectivity was 62 ± 13% at an operating fluence of 1670 J cm−2, and that the resultant short pulse driven particle acceleration and x-ray generation indicate that the on target intensity was 3.1 × 1018 W cm−2, which is indicative of a good post-plasma mirror interaction beam optical quality. By deriving the plasma mirror performance metrics from the secondary source scalings, it was simultaneously demonstrated that the plasma mirror is ready for adoption in short pulse particle acceleration and high energy photon generation experiments using the OMEGA-EP system.
Cross-beam energy transfer in direct-drive ICF. II. Theory and simulation of mitigation through increased laser bandwidth
Authors: Seaton A. G. , Yin L. , Follett R. K. , Albright B. J. , Le A.
Published: April 2022

The response of the cross-beam energy transfer instability (CBET) to laser bandwidth is investigated through a combination of theory and simulation. Existing linear theory is generalized to treat broadband lasers, demonstrating that CBET is most effectively suppressed when the bandwidth exceeds the ion-acoustic wave (IAW) frequency. It is shown that for such bandwidths, reverse (seed to pump) transfer becomes possible, which reduces the net energy transfer rapidly as bandwidth is increased. The CBET gain exponent in this regime scales with bandwidth (Δω) as Δω−3 for Gaussian or Lorentzian laser spectra with different scalings possible for other spectra. Comparison of our theory with linearized fluid and particle-in-cell simulations, performed with the laser-plasma simulation environment (LPSE) and vector particle in cell (VPIC) codes, respectively, finds that the model is accurate in the absence of nonlinear processes. However, linear analysis also finds that the IAW energy density scales as Δω−1, implying that nonlinear effects may be more difficult to control than the CBET scaling would suggest. Indeed, nonlinear effects are found to be present in VPIC simulations with high-intensity lasers, despite minimal apparent CBET. Nonlinear processes in the VPIC cases include particle trapping, the two-ion wave decay, and ion wave self-focusing. In some high intensity VPIC cases, these effects lead to net energy transfer from seed to pump and increases to backscatter stimulated Brillouin scattering reflectivities. Finally, for a given bandwidth, we show that improved control of nonlinear processes can be achieved via smoothing by spectral dispersion.
Excitonic effects at the temperature-dependent direct bandgap of Ge
Authors: Emminger Carola , Samarasingha Nuwanjula S. , Rivero Arias Melissa , Abadizaman Farzin , Menéndez José , Zollner Stefan
Published: April 2022

The temperature dependence of the complex dielectric function ϵ1+iϵ2 of bulk Ge near the direct bandgap was investigated with spectroscopic ellipsometry at temperatures between 10 and 710 K. Second derivatives of the dielectric function with respect to energy are obtained using a digital linear filter method. A model that incorporates excitonic effects using the Tanguy model for the Hulthén potential [C. Tanguy, Phys. Rev. B 60, 10660 (1999)] was used to fit the dielectric function and its second derivatives simultaneously. Using k⋅p theory and literature values for effective masses, reasonable agreement with the experiment is obtained for ϵ2 up to room temperature using the direct bandgap and its broadening as the only adjustable parameters.
Impact of fear effect and prey refuge on a fractional order prey–predator system with Beddington–DeAngelis functional response
Authors: Zhang Na , Kao Yonggui , Xie Binfeng
Published: April 2022

In this article, a fractional-order prey–predator system with Beddington–DeAngelis functional response incorporating two significant factors, namely, dread of predators and prey shelter are proposed and studied. Because the life cycle of prey species is memory, the fractional calculus equation is considered to study the dynamic behavior of the proposed system. The sufficient conditions to ensure the existence and uniqueness of the system solution are found, and the legitimacy and well posedness in the biological sense of the system solution, such as nonnegativity and boundedness, are proved. The stability of all equilibrium points of the system is analyzed by an eigenvalue analysis method, and it is proved that the system generates Hopf bifurcation nearby the coexistence equilibrium with regard to three parameters: the fear coefficient k, the rate of prey shelters p, and the order of fractional derivative q. Compared with the integer derivative, the system dynamics in the situation of fractional derivative is more stable. We observe an interesting phenomenon through the simulation: with the increase in the level of the fear effect, the stability of the positive equilibrium point changes from stable to unstable and then to stable. At this time, there are two Hopf branches nearby the positive equilibrium point with respect to the fear coefficient k, and the system can be in a stable state at very low or high level of the fear effect. In addition, when the order of the fractional differential equation of the system decreases continuously, the stability of the system will change from unstable to stable, especially in the case of low-level fear caused by predators and low rate of prey shelters. Therefore, our findings support the view that the strong memory can promote the stable coexistence of two species in the prey-predator system, while fading memory of species will worsen the stable coexistence of two species in the proposed system.
Color-tunable organic light-emitting diodes with ultrathin thermal activation delayed fluorescence emitting layer
Authors: Zhang Jiaming , Wang Yuanhe , Liu Shihao , Yu Hongwei , Zhang Letian , Xie Wenfa
Published: April 2022

Recently, organic light-emitting diodes (OLEDs) are becoming increasingly attractive to information security, wearable healthcare, and other fields. These fields propose different requirements for performances of OLEDs, especially for voltage-controlled color tunability. In this study, it is proposed to use an ultrathin layer consisting of thermally activated delayed fluorescence (TADF) material as an emitting layer of OLEDs. On the one hand, compared to devices with an ultrathin phosphorescent emitting layer, the OLEDs with TADF show observable color-tunability. On the other hand, the color-tunable OLEDs with TADF show much higher efficiency than the color-tunable fluorescent OLEDs. It demonstrates that the reverse intersystem crossing process not only enhances the exciton utilization efficiency but also leads to an insufficient host-guest energy transfer. With this strategy, a color-tunable OLED is achieved with an external quantum efficiency about 8% and shows color variations over (0.04, 0.08) when its bias voltage increases from 4 to 8 V. By combining with a patterned mask technique, the color-tunable OLEDs can potentially be applied to the field of anti-counterfeiting and status lighting.
Atomistic spin model of single pulse toggle switching in Mn2RuxGa Heusler alloys
Authors: Jakobs F. , Atxitia U.
Published: April 2022

Single femtosecond-pulse toggle switching of ferrimagnetic alloys is an essential building block for ultrafast spintronics. It is believed that for switching to occur in these ferrimagnets, the individual sublattices must have very different (element-specific) demagnetization dynamics. This suggests that ferrimagnets composed of two different elements, such as rare-earth transition-metal alloys, are necessary for switching. However, experimental observations of toggle switching in the Heusler alloy Mn2RuxGa, which has two crystallographically nonequivalent Mn sublattices with antiparallel aligned moments, have questioned these assertions. To shed some light on this question, we present an atomistic spin model for the simulation of single pulse toggle switching of Mn2RuxGa. The magnetic parameters entering our model are extracted from previous experimental observations. We show that our model is able to quantitatively reproduce the experimentally measured magnetization dynamics of single pulse toggle switching. We demonstrate that toggle switching in Mn2RuxGa is possible even when both Mn sublattices demagnetize at very similar rates, in contradiction to the previous hypothesis about the importance of element-specific demagnetization rates in this process.
A 5.7 THz GaN/AlGaN quantum cascade detector based on polar step quantum wells
Authors: Quach P. , Jollivet A. , Babichev A. , Isac N. , Morassi M. , Lemaitre A. , Yunin P. A. , Frayssinet E. , de Mierry P. , Jeannin M. , Bousseksou A. , Colombelli R. , Tchernycheva M. , Cordier Y. , Julien F. H.
Published: April 2022

We report on a GaN/AlGaN quantum cascade detector operating in the terahertz spectral range. The device was grown by metal organic chemical vapor deposition on a c-sapphire substrate and relies on polar GaN/AlGaN step quantum wells. The active region thickness is in micrometer range. The structural, electrical, and optical investigations attest of high structural quality of the synthetized nitride material. The detector exhibits a peak photocurrent at 5.7 THz (23.6 meV) with a responsivity of 0.1 mA/W at 10 K under surface normal irradiation through a 10 μm period grating. The photocurrent persists up to 20 K.
Are strongly confined colloids good models for two dimensional liquids?
Authors: Tian Jiting , Kob Walter , Barrat Jean-Louis
Published: April 2022

Quasi-two-dimensional (quasi-2D) colloidal hard-sphere suspensions confined in a slit geometry are widely used as two-dimensional (2D) model systems in experiments that probe the glassy relaxation dynamics of 2D systems. However, the question to what extent these quasi-2D systems indeed represent 2D systems is rarely brought up. Here, we use computer simulations that take into account hydrodynamic interactions to show that dense quasi-2D colloidal bi-disperse hard-sphere suspensions exhibit much more rapid diffusion and relaxation than their 2D counterparts at the same area fraction. This difference is induced by the additional vertical space in the quasi-2D samples in which the small colloids can move out of the 2D plane, therefore allowing overlap between particles in the projected trajectories. Surprisingly, this difference in the dynamics can be accounted for if, instead of using the surface density, one characterizes the systems by means of a suitable structural quantity related to the radial distribution function. This implies that in the two geometries, the relevant physics for glass formation is essentially identical. Our results provide not only practical implications on 2D colloidal experiments but also interesting insights into the 3D-to-2D crossover in glass-forming systems.
Correlation analysis of flow and sound in non-isothermal subsonic jets based on large eddy simulations
Authors: Liu Qilin , Lai Huanxin
Published: April 2022

The sound radiation mechanism is investigated in non-isothermal subsonic jets at acoustic Mach number 0.9 and at temperature ratios of 0.86, 1.0, and 2.7, using causality methods on the results predicted by large eddy simulations. Turbulence signals in the jet flows are rearranged according to the acoustic analogies, such as the streamwise and radial shear signals, ux′ and ur′, the self-signal, ui′uj′, the entropy fluctuation, s′, and the vortex norm, |ω|. The ray-tracing method is applied to locate the acoustically correlated regions, and the two-point correlation is employed to analyze the acoustic correlation. The results show that the cancelation between the s′ and ux′, and between the s′ and ur′, vary with temperature ratio, and, thus, may affect the radiation directionality. The density fluctuation, ρ′, suppresses the acoustic correlations of the shear- and self-signals in the cold jet, respectively, but strengthens them in the hot jet; thus, the ρ′ enhances the cancelation both in cold and in hot jets. The intense negative fluctuation of the ux′ is found to be associated with the cancelation mechanism. It induces the peaks of ρ′ and s′ by disturbing the average fields. The jet temperature changes the averaged density and entropy so as to change the cancelation mechanism. Two large-scale acoustically correlated parts of the coherent structures are visualized by the zonal correlation of the ρ′. Their acoustic correlations cancel each other in the hot jets, but enhance each other in the cold jets. The acoustically correlated regions represented by the zonal correlations of the s′ and |ω| are in small scale and gather around the end of the potential core region.
Flameless combustion of low calorific value gases, experiments, and simulations with advanced radiative heat transfer modeling
Authors: Nguyen Phuc-Danh , Nguyen Huu-Tri , Domingo Pascale , Vervisch Luc , Mosca Gabriel , Gazdallah Moncef , Lybaert Paul , Feldheim Véronique
Published: April 2022

Thermal radiation is the dominant mode of heat transfer in many combustion systems, and in typical flameless furnaces, it can represent up to 80% of the total heat transfer. Accurate modeling of radiative heat transfer is, thus, crucial in the design of these large-scale combustion systems. Thermal radiation impacts the thermochemistry, thereby the energy efficiency and the temperature sensitive species prediction, such as NOx and soot. The requirement to accurately describe the spectral dependence of gaseous radiative properties of combustion products interacts with the modeling of finite rate chemistry effects and conjugates heat transfer and turbulence. Additionally, because of the multiple injection of fuels and/or oxidizers of various compositions, case-specific radiative properties' expressions are required. Along these lines, a comprehensive modeling to couple radiation and combustion in reacting flows is attempted and applied to the simulation of flameless combustion. Radiation is modeled using the spectral line-based weighted-sum-of-gray-gases approach to calculate gaseous radiative properties of combustion products using the correlation of the line-by-line spectra of H2O and CO2. The emissivity weights and absorption coefficients were optimized for a range of optical thicknesses and temperatures encountered in the considered furnace. Efforts were also made on the development of a reliable and detailed experimental dataset for validation. Measurements are performed in a low calorific value syngas furnace operating under flameless combustion. This test rig features a thermal charge which can extract about 60% of combustion heat release via 80% of radiative heat transfer, making it of special interest for modeling validation. The comparison between the simulation and the experiment demonstrated a fair prediction of heat transfer, energy balance, temperature, and chemical species fields.
All-optical laser ultrasonic technique for imaging of subsurface defects in carbon fiber reinforced polymer (CFRP) using an optical microphone
Authors: Song Peng , Liu Junyan , Li Zhijie , Wu Siyuan , Sun Xiaogang , Yue Honghao , Pawlak Michal
Published: April 2022

Defects, such as delamination and debonding, are critical to the performance of carbon fiber-reinforced polymer (CFRP) composites. In recent years, non-destructive testing techniques have been improved for the inspection of these defects among CFRPs. In this study, an all-optical and non-destructive laser ultrasonic technique with an optical microphone detection module has been presented to detect the artificial subsurface defects among the CFRP composites. A finite element simulation based on the thermo-mechanical coupling model was used to study the process of nanosecond pulsed laser excitation of the CFRP laminate to produce ultrasound and the propagation behavior of ultrasound among the CFRP laminate. A series of non-contact laser ultrasonic testing experiments were carried out to study the flat bottom holes of different sizes via a laser ultrasonic detection system. The artificial subsurface defects were reliably identified by the presented all-optical laser ultrasonic system imbedded in the optical microphone using four feature images.
Flux focused series arrays of long Josephson junctions for high-dynamic range magnetic field sensing
Authors: LeFebvre Jay C. , Cho Ethan , Li Hao , Cai Han , Cybart Shane A.
Published: April 2022

Series arrays of closely spaced, planar long Josephson junctions were demonstrated to be transducers of magnetic flux featuring high-dynamic range, wide-bandwidth, and the capability to operate at cryogenic nitrogen temperatures. By tuning and scaling the geometry of these devices, it is possible to improve their sensitivity to an applied magnetic field and to generate higher voltage responses. Moreover, these devices feature linear voltage responses allowing for the potential of unlocked operation. Herein, we study the flux focusing effect in series arrays of planar Josephson junctions, which are well-suited to fabrication in thin films of the high-transition temperature superconductor YBa2Cu3O7−δ via helium focused ion beam irradiation. We present efforts to characterize the array geometry and properties for magnetic field sensing, with investigations of single Josephson junction behavior and demonstrations of small and large series arrays of Josephson junctions. Furthermore, two-tone spectroscopy is performed to quantify the practical linearity of the voltage response. In this work, a series array of 2640 long Josephson junctions is demonstrated, achieving a sensitivity of 1.7 mV/μT and a linear response over a region of 10.6 μT resulting in a dynamic range of 117 dB while operating at 40 K.
Rovibrational investigation of a new high-lying u+ state of Cu2 by using two-color resonant four-wave-mixing spectroscopy
Authors: Jin Jiaye , Zhang Qiang , Bornhauser Peter , Knopp Gregor , Marquardt Roberto , Radi Peter P.
Published: April 2022

A highly excited electronic state of dicopper is observed and characterized for the first time. The [39.6]0u+-X1Σg+(0g+) system is measured at rotational resolution by using degenerate and two-color resonant four-wave-mixing, as well as laser induced fluorescence spectroscopy. Double-resonance experiments are performed by labeling selected rotational levels of the ground state by tuning the probe laser wavelength to transitions in the well-known (1-0) band of the B0u+-X1Σg+(0g+) electronic system. Spectra obtained by scans of the pump laser in the UV wavelength range were then assigned unambiguously by the stringent double-resonance selection rules. The absence of a Q-band suggests a parallel transition (ΔΩ = 0) and determines the term symbol of the state as 0u+ in Hund’s case (c) notation. The equilibrium constants for 63Cu2 are Te = 39 559.921(92) cm−1, ωe = 277.70(14) cm−1, Be = 0.104 942(66) cm−1, and re = 2.2595(11) Å. These findings are supported by high-level ab initio calculations at the MRCI+Q level, which clearly identifies this state as resulting from a 4p ← 3d transition. In addition, three dark perturber states are found in the v = 1 and v = 2 vibrational levels of the new state. A deperturbation analysis characterizes the interaction and rationalizes the anomalous dips in the excitation spectrum of the [39.6]0u+-X1Σg+(0g+) system.
Detection and evaluation of cavitation in the stator of a torque converter using pressure measurement
Authors: Guo Meng , Liu Cheng , Liu Shiqi , Ke Zhifang , Wei Wei , Yan Qingdong , Khoo Boo Cheong
Published: April 2022

Cavitation is a transient phase transition between liquid and vapor, and it often occurs in fluid machinery, especially in a hydraulic torque converter that uses oil as the working medium to transmit speed and torque. The complex and strongly coupled fluid flow in the torque converter is prone to cavitation due to high rotating speed and high-temperature working conditions. Cavitation seriously affects the working performance, transmission smoothness, and service life of the torque converter. The flow pressure in the stator of a torque converter under various charging conditions and high rotating speeds was measured. The pressure data on the stator blade were analyzed in the time domain and frequency domain to identify and evaluate the cavitation characteristic. The transient cavitation flow inside the torque converter was also simulated with the computational fluid dynamics model. The results show that the shedding of cavitation seriously reduced the hydraulic performance, hindered the fluid flow, and destroyed the stability of the flow field. Moreover, cavitation aggravates the complexity and nonlinearity of the pressure frequency and hydraulic performance oscillation of the torque converter, and seriously affected the shaft/blade interaction frequency between the pump and stator. Meanwhile, the occurrence and degree of cavitation in the torque converter can be evaluated by APS.shaft/APS.blade (the amplitude ratio of the shaft interaction frequency and blade interaction frequency between pump and stator) with spectrum analysis of the dynamic pressure, and the critical value was 1.6 for the test torque converter. The research revealed the influence of cavitation on the internal flow field of the torque converter and provided a novel practical cavitation evaluation technique.
Anomaly detection of complex magnetic measurements using structured Hankel low-rank modeling and singular value decomposition
Authors: Zhang Xinglin , Liu Huan , Wang Zehua , Dong Haobin , Ge Jian , Liu Zheng
Published: April 2022

The magnetic anomalies generated by the ferromagnetic targets are usually buried within uncontrollable interference sources, such as the power frequency and random noises. In particular, the variability of the geomagnetic field and the low signal-to-noise ratio (SNR) of the magnetic anomalies cannot be avoided. In this paper, to improve the performance of magnetic anomaly detection (MAD) with a low SNR, we propose a novel structured low-rank (SLR) decomposition-based MAD method. In addition, a new framework based on the SLR and singular value decomposition (SVD) is constructed, dubbed SLR-SVD, and the corresponding working principle and implemented strategy are elaborated. Through comparing the SLR-SVD with two state-of-the-art methods, including principal component analysis and SVD, the results demonstrate that the proposed SLR-SVD can not only suppress the noise sufficiently, i.e., improving 55.26% approximately of the SNR, but also retain more boundary information of magnetic anomalies, i.e., decreasing approximately 68.05% of the mean squared error and improving approximately 28.47% of the structural similarity index.
Vibronic resonance along effective modes mediates selective energy transfer in excitonically coupled aggregates
Authors: Patra Sanjoy , Tiwari Vivek
Published: April 2022

We recently proposed effective normal modes for excitonically coupled aggregates that exactly transform the energy transfer Hamiltonian into a sum of one-dimensional Hamiltonians along the effective normal modes. Identifying physically meaningful vibrational motions that maximally promote vibronic mixing suggested an interesting possibility of leveraging vibrational-electronic resonance for mediating selective energy transfer. Here, we expand on the effective mode approach, elucidating its iterative nature for successively larger aggregates, and extend the idea of mediated energy transfer to larger aggregates. We show that energy transfer between electronically uncoupled but vibronically resonant donor–acceptor sites does not depend on the intermediate site energy or the number of intermediate sites. The intermediate sites simply mediate electronic coupling such that vibronic coupling along specific promoter modes leads to direct donor–acceptor energy transfer, bypassing any intermediate uphill energy transfer steps. We show that the interplay between the electronic Hamiltonian and the effective mode transformation partitions the linear vibronic coupling along specific promoter modes to dictate the selectivity of mediated energy transfer with a vital role of interference between vibronic couplings and multi-particle basis states. Our results suggest a general design principle for enhancing energy transfer through synergistic effects of vibronic resonance and weak mediated electronic coupling, where both effects individually do not promote efficient energy transfer. The effective mode approach proposed here paves a facile route toward four-wavemixing spectroscopy simulations of larger aggregates without severely approximating resonant vibronic coupling.
Spin-decoupled omnidirectional anomalous refraction based on a single metasurface
Authors: Tang Lili , Cao Yue , Jin Renchao , Wang Ying-Hua , Li Jiaqi , Wang Jin , Dong Zheng-Gao
Published: April 2022

Taking advantage of the flexible customization of dynamic and Pancharatnam–Berry phases on meta-atoms, spin-decoupled multifunctional metasurfaces have been realized for optical beams of orthogonal circularly polarized lights, which promotes the diverse development of nanophotonic devices. To date, spin-decoupled metasurfaces can only spatially split and deflect beams in coplanar directions not in non-coplanar, limiting further applications. Here, a single metasurface is proposed to experimentally as well as numerically demonstrate the spin-decoupled omnidirectional anomalous refraction. The results indicate that the three-dimensionally omnidirectional dual-beam refractions are attributed to arbitrary engineering of spin-independent phase gradients along any in-plane orientations of the single metasurface. It is believed that the proposed spin-decoupled omnidirectional metasurfaces are promising candidates for multifunctional applications in compact spin-based nanophotonic systems, such as polarized beam splitting, steering, and polarimeter.
A matrix completion algorithm for efficient calculation of quantum and variational effects in chemical reactions
Authors: Bac Selin , Quiton Stephen Jon , Kron Kareesa J. , Chae Jeongmin , Mitra Urbashi , Mallikarjun Sharada Shaama
Published: April 2022

This work examines the viability of matrix completion methods as cost-effective alternatives to full nuclear Hessians for calculating quantum and variational effects in chemical reactions. The harmonic variety-based matrix completion (HVMC) algorithm, developed in a previous study [S. J. Quiton et al., J. Chem. Phys. 153, 054122 (2020)], exploits the low-rank character of the polynomial expansion of potential energy to recover vibrational frequencies (square roots of eigenvalues of nuclear Hessians) constituting the reaction path using a small sample of its entities. These frequencies are essential for calculating rate coefficients using variational transition state theory with multidimensional tunneling (VTST-MT). HVMC performance is examined for four SN2 reactions and five hydrogen transfer reactions, with each H-transfer reaction consisting of at least one vibrational mode strongly coupled to the reaction coordinate. HVMC is robust and captures zero-point energies, vibrational free energies, zero-curvature tunneling, and adiabatic ground state and free energy barriers as well as their positions on the reaction coordinate. For medium to large reactions involving H-transfer, with the sole exception of the most complex Ir catalysis system, less than 35% of total eigenvalue information is necessary for accurate recovery of key VTST-MT observables.
Use of Bayesian statistics to calculate transient heat fluxes on compressor disks
Authors: Tang Hui , Deveney Teo , Shardlow Tony , Lock Gary D.
Published: April 2022

Future gas turbine engines require improved understanding of the heat transfer between compressor disks and air in compressor cavities under transient operating conditions. Calculation of transient heat fluxes from temperature measurements on compressor disks is a typical ill-posed inverse problem where small uncertainties of measurements can lead to large uncertainties of the calculated fluxes. This paper develops a Bayesian model for the heat flux to reduce the adverse nature of the problem by using a Gaussian prior distribution with Matérn covariance. To efficiently find the maximum a posterior, a neural network was used to solve the heat equation for compressor disks for any choice of parameters, allowing fast evaluation of the solution to the forward model for any heat flux of interest. The power of the Bayesian model is first demonstrated using numerically simulated data. Subsequently, the model is used to calculate heat fluxes from measurements of transient temperature collected from the Compressor Cavity Rig at the University of Bath. During these transient tests, the periphery of the rotating compressor disk was initially heated to a steady-state condition and then cooled rapidly by the ambient air. The fluxes for four transient cycles were calculated, with the operating range of 7.0×105<Reϕ<2.8×106, 0.0<βΔT<0.15, and 0.13<χ, where Reϕ,βΔT, and χ are the rotational Reynolds number, the buoyancy parameter, and the compressibility parameter, respectively. The results show that, for all four cases, the flow and the heat transfer in the closed cavity were initially dominated by buoyancy effects, with heat transferred from the disk to the cavity air in the outer region and reversed in the inner region. The initial heat fluxes at Reϕ=2.1×106 were higher than those at Reϕ=2.8×106 owing to a compressibility effect. During the cooling transient, for cases with Reϕ≤1.4×106, the magnitudes of the heat fluxes gradually decreased and eventually reached virtually zero. This indicated that the flow was first governed by the buoyancy effects and then became stratified. At Reϕ=2.8×106, where the rotational speed was at its maximum, buoyancy-induced flow dominated the entirety of the transient process due to significant frictional heating at the periphery of the rig. The calculated fluxes present evidence for future theoretical and computational modeling of transient disk heat transfer, and the Bayesian model provides guidance for transient temperature data analysis.
Microfluidic free interface diffusion: Measurement of diffusion coefficients and evidence of interfacial-driven transport phenomena
Authors: Nguyen Hoang-Thanh , Bouchaudy Anne , Salmon Jean-Baptiste
Published: April 2022

We have developed a microfluidic tool to measure the diffusion coefficient D of solutes in an aqueous solution by following the temporal relaxation of an initially steep concentration gradient in a microchannel. Our chip exploits multilayer soft lithography and the opening of a pneumatic microvalve to trigger the interdiffusion of pure water and the solution initially separated in the channel by the valve, the so-called free interface diffusion technique. Another microvalve at a distance from the diffusion zone closes the channel and thus suppresses convection. Using this chip, we have measured diffusion coefficients of solutes in water with a broad size range, from small molecules to polymers and colloids, with values in the range D∈[10−13–10−9] m2/s. The same experiments but with added colloidal tracers also revealed diffusio-phoresis and diffusio-osmosis phenomena due to the presence of the solute concentration gradient. We nevertheless show that these interfacial-driven transport phenomena do not affect the measurements of the solute diffusion coefficients in the explored concentration range.
Experimental investigation of effects of pulsed injection on flow structure and flame development in a kerosene-fueled scramjet with pilot hydrogen
Authors: Tian Ye , Guo Mingming , Ran Wei , Le Jialing , Zhong Fuyu
Published: April 2022

The effects of pulsed injection on the flow structure and flame development in a scramjet were investigated experimentally with a pilot hydrogen equivalence ratio (ER) of 0.1 and a kerosene ER of 0.3; the pilot hydrogen was used to enhance the kerosene combustion. In the steady injection flow, the non-reacting flow structure changed periodically, and the monitor pressure built up rapidly when the pilot hydrogen self-ignited at t = 0.0096 s, increasing from 0.03 to 0.037 MPa. The pilot flame was stable and filled the whole cavity until the kerosene began to be injected into the combustor at t = 0.05 s; the kerosene combustion occurred only in the cavity shear layer. After a very short time, the pilot flame was blown off by the kerosene. In the pulsed injection flow, the kerosene kept burning with the help of the pilot flame, and the monitor pressure remained at a high value that was about six times that in the non-reacting flow. The mixture of pilot hydrogen and kerosene flame could propagate into the isolator, which was discontinuous and a distinct fault could be seen in the flame images. The kerosene combustion under pulsed injection was very intense, and even when the pilot hydrogen was removed, the cold room-temperature kerosene could still burn steadily for some time. Comparing with the flame development process under steady injection conditions, it is concluded that pulsed injection helps greatly to realize kerosene ignition and stable combustion.
The perceived effectiveness and hidden inequity of postpandemic fiscal stimuli
Authors: Zhang Yaxin , Zheng Xinzhu , Jiang Daqian , Luo Huilin , Guo Kaidi , Song Xinke , Wang Can
Published: April 2022

Significance

Trillions in postpandemic stimuli present a prime opportunity to shape a climate-proof and equitable future. Herein, we compare the economic effectiveness and equity impacts of currently pledged stimuli and their green alternatives. Our findings reveal that while low-carbon stimuli are more effective (saving 1 million to 2 million more jobs) and more equitable (creating more jobs for low-skilled workers and decreasing global income inequality by 2 to 3%) than currently pledged stimuli on the global level, there are significant country-by-country variations. Some countries experience environmental benefits and equity at the expense of job savings as their sectoral composition and labor intensity change. Our study suggests the overall promise of green stimuli, but a careful country-specific approach in adoption.
Methylphenidate as a causal test of translational and basic neural coding hypotheses
Authors: Ni Amy M. , Bowes Brittany S. , Ruff Douglas A. , Cohen Marlene R.
Published: April 2022

Significance

Stimulants such as methylphenidate (Ritalin) are often used clinically to treat attention deficit hyperactivity disorder (ADHD) and generally to improve selective attention. Their systemic administration provides a causal manipulation of the attentional system, allowing measurements of the neuronal population changes that accompany artificially manipulated selective attention. We found that orally administering methylphenidate to rhesus monkeys selectively improved visual performance at only their attended spatial location, and that correspondingly specific changes in the shared variability of groups of neurons in visual area V4 occurred only when attention was directed toward the receptive fields of those neurons. Critically, methylphenidate changed behavior exactly when it changed the shared variability of the neuronal responses, suggesting that it may work through naturally selective cognitive mechanisms.
Bacterial lipopolysaccharide induces settlement and metamorphosis in a marine larva
Authors: Freckelton Marnie L. , Nedved Brian T. , Cai You-Sheng , Cao Shugeng , Turano Helen , Alegado Rosanna A. , Hadfield Michael G.
Published: April 2022

Significance

New surfaces in the sea are quickly populated by dense communities of invertebrate animals, whose establishment and maintenance require site-specific settlement of larvae from the plankton. Larvae selectively settle in sites where they can metamorphose and thrive largely due to inductive cues from bacteria residing on these surfaces. However, the nature of the cues used to identify “right places” has remained enigmatic. Here, we demonstrate that lipopolysaccharide, the main component of the outer membrane of Gram-negative bacteria from the bacterium
Cellulophaga lytica
, induces metamorphosis for a marine worm. We then discuss the likelihood that lipopolysaccharide provides the variation necessary to explain settlement site selectivity for many of the bottom-living invertebrate animals that metamorphose in response to bacterial biofilms.
Tracing semantic change in Portuguese
Authors: Amaral Patrícia , Tian Zuoyu , Jarrett Dylan , Torres Juan Escalona
Published: April 2022

This study uses word embeddings to investigate the semantic changes underlying the creation of two adversative connectives in Portuguese,porémandmas‘but, however’. Forporém, we chart its development from an original PP formed by a preposition with a causal meaning (por) and a demonstrative pronoun that referred anaphorically to a previous proposition (en(de)). Formas, we trace its change from an adverb meaning ‘more’. Adopting a distributional semantics approach, we use word embedding models trained on two corpora, the CIPM (Corpus Informatizado do Português Medieval, containing texts from the 12th–16th centuries) and COLONIA (containing texts from the 16th–20th centuries). We produce a measure of change based on the similarity scores ofporémandmaswith respect to words in relevant semantic categories in each corpus, representing the source and the target meanings. This paper, which constitutes the first computational study of semantic change in Portuguese, also discusses challenges and outlines steps to be taken into consideration when choosing embedding algorithms for small historical corpora.