bluuebunny/crossref_metadata_2025 huggingface dataset:
Die Ruptur des M. pectoralis major beim Hobbysportler – seltene Verletzung oder oft übersehen?
Authors: Beck Paula , Reinecke Felix , Polan Christina , Meyer Heinz-Lothar , Schoepp Christian , Burggraf Manuel , Dudda Marcel , Mester Bastian
Published: April 2022

Einleitung Die Ruptur des M. pectoralis major ist ein zwar insgesamt seltenes, bei Athleten vor allem im Kraftsport jedoch immer wieder beschriebenes Verletzungsmuster. Die Gefahr einer solchen Verletzung besteht vor allem während der exzentrischen Phase der Muskelbelastung. Ein Zusammenhang mit dem Missbrauch von anabolen Steroiden wird beschrieben, die Datenlage hierzu ist allerdings inkohärent. Wir berichten über den besonderen Fall eines jungen Patienten mit normalem Habitus, der sich im Rahmen des Breitensports eine humerale Ruptur des M. pectoralis major zugezogen hat. Anamnestisch bestand weder eine exzessive Kraftsportausübung noch ein Anhalt für die Einnahme anaboler Steroide.

Kasuistik Der 33-jährige Patient berichtete über plötzlich einschießende Schmerzen links pektoral beim Training am Butterfly-Gerät sowie ein peitschenartiges Knallgeräusch, danach hätte initial eine schmerzhafte Bewegungseinschränkung des linken Arms bestanden. Klinisch zeigten sich eine leichte Hämatomverfärbung am linksseitigen medialen Oberarm mit lokalem Druckschmerz sowie eine diskrete Asymmetrie der Kontur der Brustmuskulatur. Aufgrund der typischen Anamnese stellten wir trotz eher diskreter Klinik und laut MRT-Befundung inkompletter Ruptur die Indikation zur operativen Exploration. Intraoperativ fand sich eine vollständige Ruptur der Pars sternocostalis des M. pectoralis major mit deutlicher Retraktion und Hämatomeinblutung. Es erfolgte die Armierung und Reinsertion am Footprint mittels Titan-Ankern (2x 5,5mm Corkscrew FT Fa. Arthrex, Florida). Nach Abschluss der Rekonvaleszenzphase konnte der Patient seine sportlichen Aktivitäten auf prätraumatischem Niveau wieder aufnehmen.

Schlussfolgerung Auch bei Breitensportlern muss bei typischer Anamnese an eine Ruptur des Ansatzes des M. pectoralis major gedacht werden. Die in der Literatur beschriebene typische klinische Symptomatik bezieht sich vorwiegend auf Leistungssportler und Bodybuilder; auch beim Breitensportler kann jedoch mittels subtiler Untersuchung eine korrekte Diagnose gestellt werden. Es besteht dennoch eine erhebliche Gefahr, das Ausmaß der Verletzung zu unterschätzen. Im Zweifel sollte auch beim Breitensportler eine zeitnahe operative Exploration erfolgen. Die operative Refixierung der humeralen Ruptur des M. pectoralis major stellt den Goldstandard dar und sollte nicht nur Hochleistungsathleten vorbehalten bleiben.
Hämodialyse
Authors: Reichardt Michael
Published: April 2022

Dieser Artikel ist eine Zusammenfassung aus einer Facharbeit im Rahmen der nephrologischen Fachweiterbildung zur Gesundheits- und Krankenpflegerin in der Nephrologie an der Weiterbildungsstätte nephrologischer Zentren Rhein-Ruhr am AKK in Essen von Regina Jansen, Recklinghausen.
Recent Advances of LncRNA H19 in Diabetes
Authors: Bi Ye , Wang Yao , Sun Xianglan
Published: April 2022

Diabetes mellitus (DM) causes damage to major organs, including the heart, liver,
brain, kidneys, eyes, and blood vessels, threatening the health of the
individuals. Emerging evidence has demonstrated that lncRNAs has important
functions in the pathogenesis of human diseases, such as cancers,
neurodegenerative diseases, cardiac fibroblast phenotypes, hypertension, heart
failure, atherosclerosis and diabetes. Recently, H19, a lncRNA, has been
reported to shown to participate in the regulatory process of muscle
differentiation, glucose metabolism, and tumor metastasis, as well as
endometrial development. However, the roles of H19 in DM were still not
completely understood. This review was conducted to summarize the functions of
H19 in diabetes and discuss the challenges and possible strategies of H19 in
DM.
Hormonelle Kontrazeption und Thrombose
Authors: Hart Christina , Linnemann Birgit
Published: April 2022

Hormonelle Kontrazeption und Thromboembolie-Risiko Kombinierte hormonelle Kontrazeptiva (KK) erhöhen das VTE-Risiko signifikant. Gestagen-Monopräparate sind mit Ausnahme der 3-Monatsspritze nicht mit einem erhöhten VTE-Risiko assoziiert und können bei Frauen mit vorausgegangener VTE oder thrombophilen Risikofaktoren mit Wunsch nach hormoneller Verhütung angewandt werden.

Individuelle Risikofaktoren und hormonelle Kontrazeption Vor der Verschreibung einer hormonellen Kontrazeption soll eine sorgfältige Erhebung des VTE-Risikos erfolgen. Eine entsprechende Checkliste findet sich auf der Internetseite des BfArM. Eine routinemäßige Testung auf hereditäre Thrombophilie wird nicht empfohlen.

Kontrazeption unter Antikoagulation Orale Antikoagulanzien sind plazentagängig und prinzipiell embryotoxisch und erfordern somit die Anwendung einer sicheren Empfängnisverhütung. Eine häufige Nebenwirkung unter oraler Antikoagulanzientherapie ist das Auftreten einer Hypermenorrhö. Die hormonelle Kontrazeption kann bei bestehender Antikoagulation auch mit einem Kombinationspräparat fortgeführt werden, sofern spätestens 6 Wochen vor Beendigung der Antikoagulation die Umstellung auf eine östrogenfreie Form der Kontrazeption erfolgt.

Hormonassoziierte VTE und Rezidivrisiko VTE, die bei Frauen unter Verwendung von hormonellen Kontrazeptiva aufgetreten sind, gelten als provozierte Ereignisse. Das Rezidivrisiko einer hormonassoziierten VTE ist nach Absetzen der Antikoagulation und Umstellung auf eine östrogenfreie Form der Kontrazeption gering, sodass eine Antikoagulationsdauer von 3–6 Monaten in der Regel ausreichend ist. Nach hormonassoziierter VTE wird während einer künftigen Schwangerschaft und im Wochenbett eine medikamentöse VTE-Prophylaxe empfohlen.
When winners win, and losers lose: are altruistic views on immigration always affordable?
Authors: Rhein Susanne , Spilker Gabriele
Published: April 2022

The existing literature postulates that individual-level attitudes toward immigration are partly determined via the effect of immigration on the labor market. In particular, the labor market competition hypothesis states that natives should oppose immigrants with similar qualifications because they threaten their jobs. Empirical findings, however, partly contradict this expectation. In this paper, we argue that one needs to evaluate immigration attitudes in a broader context since the impact of immigration should be mediated by actual job market competition. In industrialized countries, the arrival of high-skilled immigrants happens against a background in which economic globalization positively affects the demand for high-skilled labor. Thus, the influx of high-skilled immigrants should rarely increase job market competition. The opposite occurs for low-skilled workers, for which labor market insecurity is enhanced by both economic globalization and immigration. We find some support for our argument using micro-level data from 19 European countries.
Tautomers of 6-thiopurine in low-temperature Ar matrices: FTIR spectroscopy analysis and quantum mechanical calculations
Authors: Ivanov A. Yu. , Stepanian S. G. , Karachevtsev V. A. , Adamovicz L.
Published: April 2022

The structures and vibrational spectra of 6-thiopurine (6TP) molecules in an isolated state were studied by the spectroscopic and computational methods. FTIR spectra of 6TP molecules isolated in low-temperature Ar matrices (at 11 K) were obtained in the infrared range 3800–200 cm–1. The optimized structures of tautomers, model clusters and the population of tautomers were estimated by the DFT, MP2 and CCSD(T) methods. The vibrational spectra were calculated by the DFT/B3LYP method with different basis sets [6–311++G(df,pd), aug-cc-pVDZ, aug-cc-pVTZ] and the MP2/aug-cc-pVDZ/anharmonic method. In the spectral range of 1700–200 cm–1 of the experimental FTIR spectra, five combination modes enhanced by the Fermi resonance were observed. Fermi resonances with the participation of librational modes of domestic molecules were found in the 600–500 cm–1 region. It was revealed that the incorporation of 6TP between the closest packing planes of Ar lattice leads to a significant increase in the frequency of two out-of-plane “butterfly” modes.
The spectral investigations of interaction between high-molecular proteins and small adenine derivates
Authors: Kudrya V. Yu. , Yashchuk V. M. , Tkachuk Z. Yu. , Gumenyuk Ya. O. , Naumenko A. P.
Published: April 2022

The spectral properties of co-systems of the DNA, RNA, and small nucleotide derivates with high-molecular π-electron-containing proteins were investigated. The positions of the first excited electronic energy levels of these compounds were verified. AT-complex in the DNA, adenine groups in the RNA/oligoadenylate, and tryptophane groups in the proteins were examined as the main triplet electronic excitations traps. The changes in fluorescence and phosphorescence spectra of the co-systems mentioned above under a variation of mutual concentrations of the oligoadenylate and protein macromolecules were observed. The spectral response of the binding of the oligoadenylate to the proteins (Human Albumin, Interferon, Immunoglobulin, Insulin) was fixed.
Micro-ring based manipulation of magnetized particles
Authors: Punyabrahma P. , Bathe R. , Jayanth G. R.
Published: April 2022

The micromanipulation of untethered magnetic particles facilitates actuation, assembly, and characterization of samples for micro- and nanotechnology applications. Conventionally, macro-scale electromagnets combined with visual servo control are employed to manipulate untethered particles. Here, we propose to employ a micro-ring actuator and a strategy based on parametric excitation for manipulation of magnetized particles against a surface in a liquid medium, which does not require visual feedback. Experimentally, the system has been employed to smoothly manipulate magnetic particles of diameter in the range 30–50 µm to move along predefined trajectories. Subsequently, the particles have been demonstrated to be manipulated into a conventionally inaccessible region beneath the re-entrant walls of a micromachined silicon chip.
Embedding of rank two supercharges in the superconformal algebra
Authors: Alvarez P. D. , Chavez R. A. , Zanelli J.
Published: April 2022

We discuss an embedding of su(n) rank two antisymmetric supercharges in the su(2, 2|dn) superalgebra, where dn = n(n − 1)/2. We describe an algorithm to construct the explicit form of the generators of the superalgebra.
Characterization methods for defects and devices in silicon carbide
Authors: Bathen M. E. , Lew C. T.-K. , Woerle J. , Dorfer C. , Grossner U. , Castelletto S. , Johnson B. C.
Published: April 2022

Significant progress has been achieved with silicon carbide (SiC) high power electronics and quantum technologies, both drawing upon the unique properties of this material. In this Perspective, we briefly review some of the main defect characterization techniques that have enabled breakthroughs in these fields. We consider how key data have been collected, interpreted, and used to enhance the application of SiC. Although these fields largely rely on separate techniques, they have similar aims for the material quality and we identify ways in which the electronics and quantum technology fields can further interact for mutual benefit.
Development of a pulsed, variable-energy positron beam for atomic scale defect studies
Authors: Jones A. C. L. , Greaves R. G. , Codding C. L. , Selim F. A.
Published: April 2022

Positron annihilation spectroscopy provides a sensitive means of non-destructive characterization of materials, capable of probing single atom vacancies in solids with 10−7 sensitivity. We detail here the development of a magnetically guided, variable energy, pulsed positron beam designed to conduct depth-dependent defect studies in metals, semiconductors, and dielectrics, which will be the first of its kind in the United States. The design of the target stage provides capabilities for measurements during in situ annealing up to 800 °C and incorporates a new approach to minimize the background due to energetic backscattered positrons. The developed beam at Bowling Green State University provides a powerful tool for characterization of thin films, devices, and ion irradiated materials.
Development of off-axis spiral phase mirrors for generating optical vortices in a range of millimeter waves
Authors: Tsujimura Toru Ii , Goto Yuki , Okada Koji , Kobayashi Sakuji , Kubo Shin
Published: April 2022

In this paper, we report the development of off-axis spiral phase mirrors that can be used to generate optical vortices from a range of millimeter waves. An obliquely incident Gaussian beam is reflected from a spiral phase mirror and is converted into an optical vortex beam with a desired topological charge. The mirrors were fabricated by mechanical machining. The designed vortex properties of reflected waves were investigated experimentally by using a low-power test, where the designed topological charge was verified based on the interference pattern between a vortex beam and a Gaussian-like beam. The designed topological charge was also estimated by using a phase retrieval method specialized for a vortex beam. These off-axis spiral phase mirrors can be used for propagation experiments of radio frequency waves with helical wavefronts in magnetized plasma.
Grain refinement leading to the ultra-high coercivity in L1-Mn1.33Ga bulk magnet via hot deformation
Authors: Lu Q. M. , Gao S. , Li Y. Q. , Zhang H. G. , Liu W. Q. , Yue M.
Published: April 2022

We achieved ultra-high coercivity of 5.65 kOe in L10-Mn1.33Ga alloy via the hot deformation (HD) method and revealed the hardening mechanism. Hot deformation led to recrystallization and grain refinement, where the average grain size was reduced to about 1.5 μm for HD-88% magnet. The coercivity mechanism indicated a weak pinning model by magnetic mini-loop analysis. It was found that small grains were formed, accompanied by a certain number of {111} ⟨11-2⟩ twins for HD magnets. The magnetic domain observation showed that both the sub-micro grain boundary and the twin boundary were acted as the pinning center of the domain wall, but the latter had weaker pinning effect. The ultra-high coercivity of the HD-88% Mn1.33Ga magnet originated mainly from the pinning of the grain boundary enhanced by grain refinement. Further grain refinement and twin structure inhibition will be promising approaches in order to obtain higher magnetic properties for L10-MnxGa bulk magnets.
Prolonging the lifetime of a compact multi-wire-layered secondary winding in the Tesla transformer
Authors: Zhao Liang , Su Jian-Cang , Li Rui , Zeng Bo , Cheng Jie , Xu Xiu-Dong , Shang Wei
Published: April 2022

A compact multi-wire-layered secondary winding for the Tesla transformer was proposed by Zhao et al. [Rev. Sci. Instrum. 88(5), 055112 (2017)]. The basic idea is to wind multiple layers of a metal wire around a polymeric base tube. However, the lifetime of this type of winding is only about 200 000 pulses, and thus it fails to meet the requirement of a lifetime of 1 × 106 pulses. In this study, two methods are developed to prolong the lifetime of this winding. One method involves replacing the original three-skin wire with a polytetrafluoroethylene (PTFE) wire. The results of small-scale experiments in different conditions show that the lifetime of the PTFE-covered copper wire is at least ten times longer than that of the three-skin wire. The other method involves improving the local structure of this winding. A strong mechanical stress is concentrated at the small end of the winding, and a highly intense electric field appears in this region, where both reduce the lifetime of the winding. Improving the local structure of the winding theoretically prolongs its lifetime by a factor of 4. Both methods were applied to the original secondary winding of a Tesla transformer and extended its theoretical lifetime by a factor of 40. The modified winding had a lifetime longer than 2 × 106 pulses without any traces of discharge. This is equivalent to a lifetime longer than that of the original winding by a factor of 10 and verifies the effectiveness of the proposed methods.
Si doping in MOCVD grown (010) β-(AlxGa1−x)2O3 thin films
Authors: Bhuiyan A. F. M. Anhar Uddin , Feng Zixuan , Meng Lingyu , Fiedler Andreas , Huang Hsien-Lien , Neal Adam T. , Steinbrunner Erich , Mou Shin , Hwang Jinwoo , Rajan Siddharth , Zhao Hongping
Published: April 2022

In this work, the structural and electrical properties of metalorganic chemical vapor deposited Si-doped β-(AlxGa1−x)2O3 thin films grown on (010) β-Ga2O3 substrates are investigated as a function of Al composition. The room temperature Hall mobility of 101 cm2/V s and low temperature peak mobility (T = 65 K) of 1157 cm2/V s at carrier concentrations of 6.56 × 1017 and 2.30 × 1017 cm−3 are measured from 6% Al composition samples, respectively. The quantitative secondary ion mass spectroscopy (SIMS) characterization reveals a strong dependence of Si and other unintentional impurities, such as C, H, and Cl concentrations in β-(AlxGa1−x)2O3 thin films, with different Al compositions. Higher Al compositions in β-(AlxGa1−x)2O3 result in lower net carrier concentrations due to the reduction of Si incorporation efficiency and the increase of C and H impurity levels that act as compensating acceptors in β-(AlxGa1−x)2O3 films. Lowering the growth chamber pressure reduces Si concentrations in β-(AlxGa1−x)2O3 films due to the increase of Al compositions as evidenced by comprehensive SIMS and Hall characterizations. Due to the increase of lattice mismatch between the epifilm and substrate, higher Al compositions lead to cracking in β-(AlxGa1−x)2O3 films grown on β-Ga2O3 substrates. The (100) cleavage plane is identified as a major cracking plane limiting the growth of high-quality Si-doped (010) β-(AlxGa1−x)2O3 films beyond the critical thicknesses, which leads to highly anisotropic and inhomogeneous behaviors in terms of conductivity.
Perfect retroreflection assisted by evanescent guided modes in acoustic metagratings
Authors: Li Xiao , Dong Daxing , Liu Jiaqing , Liu Youwen , Fu Yangyang
Published: April 2022

An acoustic metagrating (MG) constructed with an inverse-design scheme can be used to realize anomalous reflection, but its efficiency is limited. In this work, we find that the evanescent guided modes are an important component of achieving perfect retroreflection in an MG. Considering the evanescent first-order guided mode, we derive an alternative inverse-design condition to produce perfect retroreflection and improved performance in the MG parameter space compared with the traditional method. We further investigate the corresponding contribution ratios of the guided modes to perfect retroreflection and find an orthogonal relationship between the contribution ratios of odd and even guided modes. These findings are confirmed using analytical calculations and numerical simulations.
Cu-related defects and optical properties in copper–indium–selenide quantum dots by a green synthesis
Authors: Chen Guifeng , Du Qinghua , Zhang Hui , Niu Ruotong , Yuan Wenhao , Xie Xinjian , Guo Tianyu , Liu Guodong
Published: April 2022

Quantum dots of I–III–VI ternary compounds exhibit unusual photophysical properties and technological utility, which attract attention and have been intensely investigated. CuInSe2 quantum dots are an environmentally friendly composition, a direct transition, and an adjustable bandgap. Here, we discuss the influence of the Cu/In molar ratio of CuInSe2 quantum dots on Cu-related defects and photo-physical properties, and CuInSe2 quantum dots are synthesized by a green, safe, and low-temperature method in triethylene glycol. The proportion of the +1 and +2 oxidation states of Cu in the quantum dots will change with the Cu/In molar atomic ratio. The +1-oxidation state of Cu will prolong the carrier recombination lifetime and provide favorable conditions for the transfer and collection of carriers. By adjusting for different defect types, we can better apply CISe quantum dots in devices and other fields.
Observation of room-temperature amplitude mode in quasi-one-dimensional charge-density-wave material CuTe
Authors: Wang Shuyang , Chen Xuliang , An Chao , Zhou Ying , Zhang Min , Zhou Yonghui , Han Yuyan , Yang Zhaorong
Published: April 2022

We have performed in-plane electrical transport and polarized Raman spectroscopy measurements on layered material CuTe to characterize the quasi-one-dimensional charge density wave (CDW). Along with the CDW formation below TCDW ∼346 K, the a-axis resistivity shows a huge hump, but the b-axis resistivity exhibits no evident anomaly, manifesting the quasi-one-dimensional character of the CDW. Concomitantly, a rapid rise in positive Hall coefficient is observed due to partial gaping out of the Fermi surface. Based on our Raman scattering measurement, we observe two Raman-active phonon modes in the non-CDW state and, additionally, one collective amplitude mode and four zone-folded modes in the CDW state. The phonon-mode shift with temperature clearly deviates from the expected anharmonic model upon approaching TCDW, suggesting strong electron–phonon coupling in driving the CDW transition. The amplitude mode even survives at room temperature and above, whose evolution can be described by a modified mean-field model, indicating a well-defined CDW order. These results, in addition to the simple formula and easy-to-exfoliate layered structure, promise CuTe as a model system to study the Peierls-like CDW physics and hold great potentials for CDW-based applications.
Investigation of veryintenseD3-band emission in multi-crystalline silicon wafers using electron microscopy and hyperspectral photoluminescence imaging
Authors: Thøgersen Annett , Jensen Ingvild J. T. , Graff Joachim S. , Gudem Ringdalen Inga , Almeida Carvalho Patricia , Mehl Torbjørn , Zhu Junjie , Burud Ingunn , Olsen Espen , Søndenå Rune
Published: April 2022

Defects in high performance multi-crystalline silicon wafers can be detrimental to the lifetime of the solar cell. It is, therefore, important to study and understand the underlying structure and chemical elements present at these defective areas in order to suppress them. The underlying cause of the D-band emission line “veryintenseD3” (VID3) has not yet been understood, although many theories have been proposed. In this paper, we have investigated the underlying causes of the d-band emission peak VID3 by hyperspectral photoluminescence imaging, scanning electron microscopy, electron backscatter diffraction, scanning transmission electron microscopy, and density functional theory (DFT) to understand the defect structure in areas of a VID3 emission peak in more detail. We found a high VID3 peak intensity at sub-grain and Σ3 twin boundaries bordering to grains with a small misorientation, which suggests higher stress in these regions. Defects close to the twin boundary indicate a light element dopant in the area, such as oxygen. DFT calculations show that oxygen is prone to segregate to this boundary.
Effects of electronic correlation on the high harmonic generation in helium: A time-dependent configuration interaction singles vs time-dependent full configuration interaction study
Authors: Woźniak Aleksander P. , Przybytek Michał , Lewenstein Maciej , Moszyński Robert
Published: April 2022

In this paper, we investigate the effects of full electronic correlation on high harmonic generation in the helium atom subjected to laser pulses of extremely high intensity. To do this, we perform real-time propagations of helium atom wavefunction using quantum chemistry methods coupled to Gaussian basis sets. Calculations are performed within the real-time time-dependent configuration interaction framework at two levels of theory: time-dependent configuration interaction with single excitations (uncorrelated method) and time-dependent full configuration interaction (fully correlated method). The electronic wavefunction is expanded in Dunning basis sets supplemented with functions adapted to describing highly excited and continuum states. We also compare the time-dependent configuration interaction results with grid-based propagations of the helium atom within the single-active-electron approximation. Our results show that when including the dynamical electron correlation, a noticeable improvement to the description of high harmonic generation (HHG) can be achieved in terms of, e.g., a more constant intensity in the lower energy part of the harmonic plateau. However, such effects can be captured only if the basis set used suffices to reproduce the most basic features, such as the HHG cutoff position, at the uncorrelated level of theory.
Molecular rotors to probe the local viscosity of a polymer glass
Authors: Mirzahossein Elham , Grzelka Marion , Pan Zhongcheng , Demirkurt Begüm , Habibi Mehdi , Brouwer Albert M. , Bonn Daniel
Published: April 2022

We investigate the local viscosity of a polymer glass around its glass transition temperature by using environment-sensitive fluorescent molecular rotors embedded in the polymer matrix. The fluorescence of the rotors depends on the local viscosity, and measuring the fluorescence intensity and lifetime of the probe therefore allows us to measure the local free volume in the polymer glass when going through the glass transition. This also allows us to study the local viscosity and free volume when the polymer film is put under an external stress. We find that the film does not flow homogeneously but undergoes shear banding that is visible as a spatially varying free volume and viscosity.
Nonadiabatic instanton rate theory beyond the golden-rule limit
Authors: Trenins George , Richardson Jeremy O.
Published: April 2022

Fermi’s golden rule (GR) describes the leading-order behavior of the reaction rate as a function of the diabatic coupling. Its asymptotic (ℏ → 0) limit is the semiclassical golden-rule instanton rate theory, which rigorously approximates nuclear quantum effects, lends itself to efficient numerical computation, and gives physical insight into reaction mechanisms. However, the golden rule by itself becomes insufficient as the strength of the diabatic coupling increases, so higher-order terms must be additionally considered. In this work, we give a first-principles derivation of the next-order term beyond the golden rule, represented as a sum of three components. Two of them lead to new instanton pathways that extend the GR case and, among other factors, account for effects of recrossing on the full rate. The remaining component derives from the equilibrium partition function and accounts for changes in potential energy around the reactant and product wells due to diabatic coupling. The new semiclassical theory demands little computational effort beyond a GR instanton calculation. It makes it possible to rigorously assess the accuracy of the GR approximation and sets the stage for future work on general semiclassical nonadiabatic rate theories.
Modeling of surface roughness effects on bypass and laminar separation bubble-induced transition for turbomachinery flows
Authors: Zhang Yang , Xu Jiakuan , Li Yi , Qiao Lei , Bai Junqiang
Published: April 2022

In a previous study, we developed a one-equation transition model for the bypass and laminar separation bubble (LSB)-induced transition based on local variables. In this paper, distributed surface roughness effects are taken into account by constructing a new transport equation for the roughness amplification factor Ar. Modified criteria taking account of Ar are proposed to describe the roughness effects on the bypass and LSB-induced transitions. Moreover, to predict the flow properties in the laminar–turbulent region more accurately, a modified boundary condition for rough surfaces is employed. The calculations show that, overall, the rough wall promotes the bypass transition and reduces the size, or even causes the disappearance, of the LSBs. Good agreement of the numerical results from the proposed model with the experimental data indicates that the present roughness correction formula is reasonable and accurate.
NQCDynamics.jl: A Julia package for nonadiabatic quantum classical molecular dynamics in the condensed phase
Authors: Gardner James , Douglas-Gallardo Oscar A. , Stark Wojciech G. , Westermayr Julia , Janke Svenja M. , Habershon Scott , Maurer Reinhard J.
Published: April 2022

Accurate and efficient methods to simulate nonadiabatic and quantum nuclear effects in high-dimensional and dissipative systems are crucial for the prediction of chemical dynamics in the condensed phase. To facilitate effective development, code sharing, and uptake of newly developed dynamics methods, it is important that software implementations can be easily accessed and built upon. Using the Julia programming language, we have developed the NQCDynamics.jl package, which provides a framework for established and emerging methods for performing semiclassical and mixed quantum–classical dynamics in the condensed phase. The code provides several interfaces to existing atomistic simulation frameworks, electronic structure codes, and machine learning representations. In addition to the existing methods, the package provides infrastructure for developing and deploying new dynamics methods, which we hope will benefit reproducibility and code sharing in the field of condensed phase quantum dynamics. Herein, we present our code design choices and the specific Julia programming features from which they benefit. We further demonstrate the capabilities of the package on two examples of chemical dynamics in the condensed phase: the population dynamics of the spin-boson model as described by a wide variety of semiclassical and mixed quantum–classical nonadiabatic methods and the reactive scattering of H2 on Ag(111) using the molecular dynamics with electronic friction method. Together, they exemplify the broad scope of the package to study effective model Hamiltonians and realistic atomistic systems.
Strong quantum-confined excitation and emission from violet phosphorus quantum dots
Authors: Zhan Y. W. , Yan K. , Wu J. H. , Zhu H. G. , Chen J. , Tang S. L. , Zhang Z. Y. , Wu X. L.
Published: April 2022

As a new type of two-dimensional semiconductor material, violet phosphorus (VP) has recently attracted much attention for applications in the field of optoelectronics. Although mechanical exfoliation has been used to prepare VP nanoribbons or nanosheets, production of the high quantum yield VP quantum dots (VPQDs) remains a challenge. Herein, the VPQDs are prepared via liquid exfoliation in ethanol and subsequent solvothermal treatment under 180 °C in dimethylformamide. The prepared VPQDs have a mean size of about 2 nm and can emit a strong blue photoluminescence (PL) when exchanged in ethanol solution. The quantum yield can reach 8.6%. The strong PL arises from both the band-to-band recombination related to quantum confinement effects and P-O-C related surface bonding state. Furthermore, the VPQDs solution has a good photostability under ambient conditions, suggesting their possible potential in fluorescent biological imaging and photocatalytic reactions.
Observation of a four-spin solid effect
Authors: Tan Kong Ooi , Griffin Robert G.
Published: April 2022

The two-spin solid effect (2SSE) is one of the established continuous wave dynamic nuclear polarization mechanisms that enables enhancement of nuclear magnetic resonance signals. It functions via a state-mixing mechanism that mediates the excitation of forbidden transitions in an electron–nuclear spin system. Specifically, microwave irradiation at frequencies ωμw ∼ ω0S ± ω0I, where ω0S and ω0I are electron and nuclear Larmor frequencies, respectively, yields enhanced nuclear spin polarization. Following the recent rediscovery of the three-spin solid effect (3SSE) [Tan et al., Sci. Adv. 5, eaax2743 (2019)], where the matching condition is given by ωμw = ω0S ± 2ω0I, we report here the first direct observation of the four-spin solid effect (4SSE) at ωμw = ω0S ± 3ω0I. The forbidden double- and quadruple-quantum transitions were observed in samples containing trityl radicals dispersed in a glycerol–water mixture at 0.35 T/15 MHz/9.8 GHz and 80 K. We present a derivation of the 4SSE effective Hamiltonian, matching conditions, and transition probabilities. Finally, we show that the experimental observations agree with the results from numerical simulations and analytical theory.
Bright lights are loud; violet shrieks and red hums
Authors: Barretto Jerry T
Published: April 2022

An analogy to help address the abstract, non-intuitive nature of discrete energy levels and frequencies associated with allowed transitions is presented. The analogy uses notes on a stave as the base and attributes of the target such as intensity and frequency are discussed. Several limitations and implications for use are enumerated.
Demonstrating acoustic camouflage with ultrasonic sensors in the laboratory
Authors: Neel Matthew S
Published: April 2022

Similar to how stealth materials were developed to reduce the radar wave energy returning from an aircraft, here we explore a low-cost laboratory demonstration that uses similar principles to prevent detection of an object by an ultrasonic sensor. This demonstration setup can be used as a starting point to encourage students to explore the surface properties of materials and the ways in which ultrasonic ranging sensors operate.
Striations in dual-low-frequency (2/10 MHz) driven capacitively coupled CF4 plasmas
Authors: Wang Xiao-Kun , Wang Xiang-Yu , Liu Yong-Xin , Schulze Julian , Donkó Zoltán , Wang You-Nian
Published: April 2022

In electronegative radiofrequency plasmas, striations (STRs) can appear if the bulk plasma is dominated by positive and negative ions that can react to the driving frequency. Here, we investigate such self-organized structures in dual-frequency (2/10 MHz) capacitively coupled CF4 plasmas by phase-resolved optical emission spectroscopy and particle-in-cell/Monte Carlo collision simulations. This choice of the frequencies is made to ensure that the ions can react to both the lower (2 MHz, ‘low frequency’, LF) and the higher (10 MHz, ‘high frequency’, HF) components of the excitation waveform. A strong interplay of the two excitation components is revealed. As the STRs appear in the plasma bulk, their number depends on the length of this region. By increasing the LF voltage, ϕ
LF, the sheath widths at both electrodes increase, the bulk is compressed and the number of STRs decreases. The maximum ion density decreases slightly as a function of ϕ
LF, too, due to the compressed plasma bulk, while the minimum of the ion density remains almost constant. The spatio-temporal distributions of the excitation and ionization rates are modulated both by the LF and HF with maxima that occur at the first HF period that follows the complete sheath collapse at a given electrode. These maxima are caused by a high local ambipolar electric field. At a given phase within a HF period the current density is different at different phases within the LF period because of frequency coupling. The LF components of the F− ion velocity and of the electric field are much lower than the respective HF components due to the lower LF component of the displacement current in the sheaths. The LF component of the total current is dominated by the ion current at low values of ϕ
LF but by the electron current at high values. The HF component of the total current is dominated by the electron current and decreases slightly as a function of ϕ
LF.
Theory of non-equilibrium ‘hot’ carriers in direct band-gap semiconductors under continuous illumination
Authors: Sarkar Subhajit , Un Ieng-Wai , Sivan Yonatan , Dubi Yonatan
Published: April 2022

The interplay between the illuminated excitation of carriers and subsequent thermalization and recombination leads to the formation of non-equilibrium distributions for the ‘hot’ carriers and to heating of both electrons, holes and phonons. In spite of the fundamental and practical importance of these processes, there is no theoretical framework which encompasses all of them and provides a clear prediction for the non-equilibrium carrier distributions. Here, a self-consistent theory accounting for the interplay between excitation, thermalization, and recombination in continuously-illuminated semiconductors is presented, enabling the calculation of non-equilibrium carrier distributions. We show that counter-intuitively, distributions deviate more from equilibrium under weak illumination than at high intensities. We mimic two experimental procedures to extract the carrier temperatures and show that they yield different dependence on illumination. Finally, we provide an accurate way to evaluate photoluminescence efficiency, which, unlike conventional models, predicts correctly the experimental results. These results provide a starting point towards examining how non-equilibrium features will affect properties hot-carrier based application.
Highly absorptive and mechanically stable double perovskites Cs2SnI6 and Cs2SnKrI6
Authors: Soni Yashaswi , Agrawal Rohit , Pachori Sanjay , Shukla Akash , Verma Ajay Singh
Published: April 2022

Numerous double perovskites have demonstrated their astonishing potential in several optoelectronic and optical communication areas. Cs2SnI6 has also attracted attention because of its unique vacancy-ordered structure. However, Cs2SnI6 fitted them as good absorbing material still we have attempted to dope Kr atom at the vacancy site to intensify absorption. Herein, we have enumerated the structural, electronic, optical, mechanical and thermoelectric properties of Cs2SnI6 and Cs2SnKrI6. All these physical properties have been computed using density functional theory based Wien2K simulation code. Cs2SnKrI6 exhibits the indirect band gap of ∼ 1.36 eV and direct band gap of ∼ 1.37 eV. Cs2SnI6 and Cs2SnKrI6 both are optically active in visible and near-infrared regions with high absorption. The optical conductivity and power factor are also increased to a substantial level after doping. We have studied the elastic properties to examine the mechanical stability of these materials. We have found B/G ratio of 2.64 and 2.07 for Cs2SnI6 and Cs2SnKrI6 respectively, which demonstrates the ductile nature. After getting these constructive results, we have concluded that power conversion efficiency will also stimulate up to a great extent by doping.
Multiple-image encryption algorithm based on genetic central dogma
Authors: Zhang Xiaoqiang , Tian Jingxi
Published: April 2022

A large number of images are generated and distributed in various fields every day. To protect the image information from being stolen during the network transmission, this paper proposes a multiple-image encryption algorithm based on genetic central dogma and three-dimensional (3D) bit planes. This paper simulates the genetic central dogma and defines the 3D bit planes. Firstly, k original images are transformed into 8-bit binary and converted into a 3D matrix; secondly, the 3D matrix is permutated by rotating the bit plane and performing permutation among the bit planes; thirdly, we encode the scrambled 3D matrix into DNA codes. The diffusion is realized by imitating the genetic central dogma and introducing RNA mutations; finally, the encrypted images are obtained by the RNA decoding operation. Experimental results and algorithm analyses indicate that the proposed algorithm has strong security and desirable performance.
Testing the quantum effects near the event horizon with respect to the black hole shadow *
Authors: Xu Zhaoyi , Tang Meirong
Published: April 2022

In recent years, the study of quantum effects near the event horizon of a black hole (BH) has attracted extensive attention. It has become one of the important methods to explore BH quantum properties using the related properties of a quantum deformed BH. In this work, we study the effect of a quantum deformed BH on the BH shadow in two-dimensional Dilaton gravity. In this model, quantum effects are reflected by the quantum correction parameter m. By calculation, we find that: (1) the shape of the shadow boundary of a rotating BH is determined by the BH spin a, the quantum correction parameter m, and the BH type parameter n; (2) when the spin

, the shape of the BH shadow is a perfect circle; when

, the shape is distorted; if the quantum correction parameter

, their shapes reduce to the cases of a Schwarzschild BH and Kerr BH, respectively; (3) the degree of distortion of the BH shadow is different for various quantum correction parameters m; with an increase in the parameter m, the boundary of the BH shadow expands; (4) the size of the BH shadow varies greatly with respect to various quantum deformed BHs (n), and the change in BH shadow shape caused by parameter n is similar to that caused by parameter m, which indicates that there is a "degenerate phenomenon" between the two parameters. Because the value of m in actual physics should be very small, the current observations of the event horizon telescope (EHT) cannot distinguish quantum effects from the BH shadow. In future BH shadow measurements, it will be possible to distinguish quantum deformed BHs, which will help to better understand the quantum effects of BHs.
Dynamic adaptive security path planning based on A* algorithm
Authors: Lu Fan , Han Cao , Wu Ganwenxiang , Lu Mingrui , Yang Jikun , Miao Baorui , Ma Yingjie
Published: April 2022

Aiming at the problems of large memory consumption, long operation time and low security of traditional A * algorithm, a dynamic adaptive improved algorithm based on A * algorithm is proposed. Firstly, according to the heuristic function of the proportion of obstacles in the map, the adaptive dynamic weighting is carried out to shorten the search time. Secondly, the jump point search (JPS) algorithm is integrated to remove a large number of redundant points and improve the running speed of the algorithm. Finally, according to the relative position of the starting point and the target point, the obstacles are expanded dynamically to keep a safe distance between the planned path and the obstacles. In order to verify the effect, the improved algorithm is tested in different sizes and different proportion of obstacles. The results show that the improved algorithm is efficient and safe in global path planning.
Neural Network Based Model for Friction Potential Estimation under Longitudinal and Lateral Excitations
Authors: Todorovic Smiljana , Wagner Andreas , Müller Sven , Neubeck Jens
Published: April 2022

Information about the maximum tire-road friction coefficient secures safety, increases the performance of ADAS functions, and enables higher levels of automation. An important parameter representing the relation between maximal longitudinal or lateral forces and normal force is friction potential. This paper presents a new approach for friction potential estimation based on Neural Networks by using data of 4WD vehicle. The regression model built in this paper can estimate the friction potential under both, longitudinal and lateral excitations. The goal was to build an estimation model, which does not require a tire model and can work under different types of excitations. Furthermore, this paper confirms, that the neural network approach requires lower excitations for friction potential estimation in comparison to traditional approaches. Data for training and validation was collected using a research vehicle called FlexCar, which was designed, built, and automated in the project with the same name. Experiments were conducted on three different friction levels.
Joint segmentation of optic cup and optic disc using deep convolutional generative adversarial network
Authors: Yu Linfang
Published: April 2022

Glaucoma, as one of the three major blinding ophthalmic diseases in the world, is usually accompanied by changes in the structure of the patient’s optic disc, such as optic disc atrophy and depression. Clinical ophthalmologists tend to use the cup-disc ratio as an evaluation index to realize the screening and diagnosis of glaucoma. Therefore, the accurate measurement of optic cup (OC), optic disc (OD) and other parameters is of great clinical significance for early screening of glaucoma. Inspired by game theory, this paper combines deep convolutional neural networks (DCNN) with generative adversarial networks (GAN), and proposes a model for the joint segmentation of OC and OD. Specifically, the generator is composed of a deep convolutional encoder-decoder network to jointly segment the OC and OD, and the discriminator is composed of an eight layer full convolutional neural network. The discrimination results adjust the parameters in the structure of the generator and discriminator network through back propagation to achieve the effect of autonomous learning and optimization of the model. When the proposed network and the existing networks are evaluated on the public dataset Drishti-GS1, the research results demonstrate that the proposed network can achieve a significant improvement in the overall performance.
Lightweight spatial pyramid pooling network for real-time semantic segmentation
Authors: Jiang Peilong , Ke Xiao
Published: April 2022

In recent years, the state-of-the-art semantic segmentation models have made extremely successful in various challenging scenes. However, the high computation costs of these models make it difficult to deploy to mobile devices. To better serve in computation constraint scenes, the semantic segmentation model should not only have high segmentation performance, but also fast inference speed. In this paper, we proposed an efficient multi-scale context module named LSPPM, which can gather abundant context information at a low computation cost. Base on this, we present a real-time semantic segmentation model called LSPPNet which is specially designed for real-time application. We have done an exhaustive experiment to evaluate LSPPNet in the challenge urban street scenes datasets Cityscapes. Extensive experiment shows that LSPPNet gets a better trade-off between segmentation performance and inference speed. We test LSPPNet on an NVIDIA 2080 super graphics card and it can achieve 75.8% MIoU in Cityscapes test set in real-time speed.
Design and implementation of the whole process collaborative system for software development
Authors: Kai Wang
Published: April 2022

With the increasingly urgent and arduous task of software development, software engineering development tools that can efficiently respond to the continuous changes in software requirements, rationally plan the software development process, and control the development cost will be widely used in software engineering. In response to actual needs, the supporting tool is designed to meet the system requirements, software requirements and software design and development. First, we use visualization modeling optimization technology of structured analysis and design method to build demand analysis models and system design models; Secondly, the dynamic verification technology of data model logical consistency is adopted to verify the logical consistency of data model in evolution; finally, the verification of the system model is achieved through hierarchical flow diagrams, fully expanded flow diagrams and statistical views. The vehicle cruise control system is selected for application verification, and the tool meets the requirements of software development and improves the software quality.