bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonlinear wave interactions in a transitional hypersonic boundary layer
Authors: Zhang Chuanhong , Shi Zhiwei
Published: October 2022

The linear and nonlinear evolutions and breakdown of the second modes in hypersonic boundary layers (HBLs) on a flared cone are investigated using Rayleigh-scattering flow visualization and fast-response pressure sensors. Based on two spatially separated pressure signals, cross-bicoherence analysis that permits the distinction of sum- and difference-interactions is utilized to identify the nonlinear interactions. In addition, the visualization temporal and spatial resolution allows fine flow features to be captured to provide additional flow information. Amplitude correlation technique is used to estimate the nonlinear energy transfer between the modes. Our results show that nonlinear interactions between the second mode and the low-frequency wave contribute to the growth of the low-frequency wave, and the difference interactions between the second mode and its first harmonic play a dominant role in modulating the waves in the overall transition process. Amplitude correlation analysis reveals that the spectral energy is nonlinearly transferred from the second mode into its first harmonic and into low-frequency wave, in agreement with the cross-bicoherence analysis. The amplitude modulation of the second mode caused by the difference interaction between the second mode and its first harmonic will reduce the propagation speed of the second mode. However, at the final breakdown stage, this difference interaction vanishes, and the second-mode propagation velocity recovers quickly. Since the frequency of the second mode keeps almost unchanged over the entire transition process, a higher propagation velocity will result in a larger wavelength, indicating an elongation and deformation of the second mode. Eventually, the difference interaction between the second mode and the low-frequency wave accompanying the energy transfer from the second mode to low-frequency waves leads to the final breakdown of the HBLs into a turbulent state.
Controlling flow separation over a curved ramp using vortex generator microjets
Authors: Pour Razzaghi Mohammad Javad , Masoumi Yasin , Rezaei Sani Seyed Mojtaba , Huang Guoping
Published: October 2022

Introducing a fluid microjet into the boundary layer to increase fluid momentum and hence delay separation is a method for actively controlling a flow separation region. The present work numerically analyzed the control of a separation bubble behind a ramp. For this purpose, we first verified the steady-state numerical results for a flow (without a jet) over the ramp against reliable experimental studies from the literature. Next, the effects of introducing a microjet to the flow were also verified. A jet was then placed at three different distances above the ramp to study its impact on various parameters, including velocities, Reynolds stresses, pressure, vorticity, streamlines, and the separation bubble size. As the jet was moved further back, the jet-induced upwash region grew considerably. Finally, the effects of using three identical jets were studied and compared against those of a single jet. The results indicated that using a three-jet array shrank the separation bubble. Using an array with d/D = 15 (distance between microjets over microjet diameter) can limit laterally the separation bubble about 2.75 times smaller than a single jet in the z-direction. Also, the employment of the jet managed to decrease the length of the separation zone in the x-direction up to 78%, in the case of Lx/L1 = 0.0143 (longitudinal distance of microjet from above the ramp over ramp length) and d/D = 10.
Galileo Galilei. Scientific Heavyweight, Political Lightweight
Authors: Kastrup Helge , Mallow Jeffry V.
Published: October 2022

Galileo can be called the first modern scientist. He argued that the Bible shows the way to heaven, not the way the heavens behave. His scientific achievements went well beyond gravity and the Earth's motion. His study of gravity was an example of genius cutting though the peripheral to grasp the essential; in this case that for compact bodies, gravity trumped air resistance. His study of forces predated Newton by the better part of a century. The latter's First Law is actually Galileo's.

Galileo's work brought him into conflict with Church doctrine. His claim that the Earth moved earned him permanent house arrest.
Isaac Newton. Peerless Polymath
Authors: Kastrup Helge , Mallow Jeffry V.
Published: October 2022

Newton's first law, inertia: “A body at rest or in motion continues at the same speed and in the same direction unless acted upon by an external force,” was actually discovered by Galileo. The second law, “Force = mass x acceleration,” is a demonstration of genius akin to that of Galileo. Galileo recognized the importance of gravity over air resistance; Newton recognized the importance of applied force over friction. Together with the third law, “action–reaction,” the triad constituted a complete description of motion.

His law of gravitation described not only the motion of the planets but also the force between any two objects in the universe. He discovered calculus and invented the reflecting telescope. However, he actually spent more time on alchemy and Bible studies than on physics. At the age of 54, he became director of the Royal Mint, using his energies to detect counterfeiting and attending the hangings of the culprits.
Niels Bohr. Rule Breaker
Authors: Kastrup Helge , Mallow Jeffry V.
Published: October 2022

Niels Bohr made numerous contributions to physics. But his most important was to break the rules. Bohr propounded several postulates. First, that electrons revolved in their orbits around the nucleus of an atom without emitting energy. Second, that spectral lines came from electrons emitting energy by jumping from one orbit to a lower one. Third, that only certain orbital radii were allowed. All three of these unsubstantiated claims violated classical physics, according to which accelerating charges emit energy. Thus, electrons should lose their energy and spiral into the nucleus. But this theory could not account for spectra; Bohr's postulates could. Bohr was the leader of a brilliant group of physicists who developed most of the fundamentals of quantum mechanics and showed that its laws proved the validity of his inspired guesses. A non-member of the group was Einstein, who disagreed with his friend Bohr over the actual meaning of quantum mechanics.
Lise Meitner. Breaking Up the Nuclear Family
Authors: Kastrup Helge , Mallow Jeffry V.
Published: October 2022

In the early days of nuclear physics, several problems were prominent. One was how to explain why the disintegration of a uranium atom was accompanied by the release of an enormous amount of energy. Lise Meitner and her nephew Otto Frisch solved the problem: nuclear fission. The uranium split into two smaller elements, barium and krypton. The sum of their masses is less than that of the uranium. The energy produced, E, was the result of the conversion of that extra mass per Einstein's equation E = mc2. The second problem was why elements beyond uranium were unstable. In the nucleus, there are two competing forces: electric repulsion between the protons and a strong attractive force. The latter dominates the former until the number of protons is so large that the situation reverses, causing the nucleus to fission. Meitner and Frisch showed that the number is 92, the atomic number of uranium. All heavier elements can only be produced artificially.

Born Jewish, Meitner converted to Lutheranism. This counted for nothing after Hitler came to power. She fled Germany, eventually immigrating to Sweden. As later archives have revealed, she was denied a well-deserved Nobel Prize.
George Gamow. A Physicist in Wonderland
Authors: Kastrup Helge , Mallow Jeffry V.
Published: October 2022

George Gamow's accomplishments were many. He solved the problem of nuclear decay by alpha-particle emission. An alpha particle is a helium nucleus. It is emitted, for example, in the transmutation of uranium to thorium. But the energy needed to exit the uranium nucleus exceeds the energy that the alpha particle contains. Gamow explained the effect as “tunneling.” The alpha is both a particle and a wave. Some small part of the wave can exceed the boundaries of the nucleus; thus, there is some small probability that an alpha gets out. One of Gamow's papers was co-authored with his student Ralph Alpher. In a well-known story (at least to physicists), Gamow asked fellow physicist Han Bethe (pronounced “beta”) to add his name as co-author, although he had nothing to do with the research. This then became known as the Alpher–Bethe–Gamow paper (read αβγ). Less well known is that Alpher was annoyed and that Bethe later said the paper was wrong. Gamow also studied the origins of the universe.

A prolific popularizer of science, Gamow wrote several books, among them One Two Three … Infinity, Thirty Years that Shook Physics, and the Mr. Tomkins series.
Richard P. Feynman. The Safecracker Cracks Quantum Electrodynamics
Authors: Kastrup Helge , Mallow Jeffry V.
Published: October 2022

As a young physicist working on the top-secret Manhattan Project, Richard Feynman noticed that some people did not bother to close their safes at night. For those that were closed, Feynman was often able to guess the combinations in the way that current hackers guess passwords: using personal information like birthdates or scientific numbers that his colleagues thought were too clever to be guessed. Feynman was an inveterate problem solver. The greatest problem he solved was how to connect the classical electrodynamics of Maxwell with modern quantum mechanics. Called quantum electrodynamics (QED), the theory described the interaction of light with matter. QED was able to explain anomalies for which ordinary quantum mechanics could not account and much more. Feynman's anecdotes are too numerous to list in an abstract. Suffice it to say that not only was he a safecracker, but a brilliant lecturer, a popular author, and a bongo player.
Margaret Burbidge. Against all Odds
Authors: Kastrup Helge , Mallow Jeffry V.
Published: October 2022

In 1945, Margaret Burbidge was denied a fellowship to work at the Mt. Wilson Observatory, reserved for men only. In 1955, she finally gained access by posing as her husband's assistant but was forced to live apart from him to maintain the charade. In 1957, she was part of the team known as B2FH: Burbidge, Burbidge, Fowler, and Hoyle. She and her husband Geoffrey, along with William Fowler and Fred Hoyle, derived the mechanism by which stars produce the elements. In 1972, she was awarded the directorship of the Royal Greenwich Observatory but uniquely denied the concomitant title of Astronomer Royal. Burbidge also carried out studies of quasars, participated in the design of a spectrometer for the Hubble telescope, and was part of the team that identified a massive black hole in a galaxy. She has an asteroid named after her. She was active in research until her death in 2020 at age 100. She was a leader in the fight to end gender discrimination against women in astronomy.
Vera Rubin. Solver of Problems, Arcane and Mundane
Authors: Kastrup Helge , Mallow Jeffry V.
Published: October 2022

Already in her Ph.D. thesis in 1954, Vera Rubin broke new ground. She demonstrated that galaxies are clumped rather than evenly distributed in space—a surprising and crucial finding, the importance of which was not recognized until many years later. Her exhaustive study of galactic motion produced major discoveries. Two stand out. The first was that the universe expansion was anisotropic. Before Rubin's measurements, it was assumed that the expansion was the same in all directions. Rubin showed that this was incorrect: one part of the universe was expanding faster. The second came from her measurements of galactic rotation. Rapidly moving spiral-shaped galaxies should fly apart, but they do not. The only thing that can hold them together is a large amount of invisible mass, about five to ten times the amount observed in the galaxy itself. This is now called “dark matter” and the conundrum of its presence is one of the major areas of astrophysical research.

Rubin was denied permission to work at Mt. Palomar, with the excuse that there were no facilities for women. She solved the problem by building her own bathroom.
Mind blanking is a distinct mental state linked to a recurrent brain profile of globally positive connectivity during ongoing mentation
Authors: Mortaheb Sepehr , Van Calster Laurens , Raimondo Federico , Klados Manousos A. , Boulakis Paradeisios Alexandros , Georgoula Kleio , Majerus Steve , Van De Ville Dimitri , Demertzi Athena
Published: October 2022

Mind blanking (MB) is a waking state during which we do not report any mental content. The phenomenology of MB challenges the view of a constantly thinking mind. Here, we comprehensively characterize the MB’s neurobehavioral profile with the aim to delineate its role during ongoing mentation. Using functional MRI experience sampling, we show that the reportability of MB is less frequent, faster, and with lower transitional dynamics than other mental states, pointing to its role as a transient mental relay. Regarding its neural underpinnings, we observed higher global signal amplitude during MB reports, indicating a distinct physiological state. Using the time-varying functional connectome, we show that MB reports can be classified with high accuracy, suggesting that MB has a unique neural composition. Indeed, a pattern of global positive-phase coherence shows the highest similarity to the connectivity patterns associated with MB reports. We interpret this pattern’s rigid signal architecture as hindering content reportability due to the brain’s inability to differentiate signals in an informative way. Collectively, we show that MB has a unique neurobehavioral profile, indicating that nonreportable mental events can happen during wakefulness. Our results add to the characterization of spontaneous mentation and pave the way for more mechanistic investigations of MB’s phenomenology.
Evolution avoids a pathological stabilizing interaction in the immune protein S100A9
Authors: Harman Joseph L. , Reardon Patrick N. , Costello Shawn M. , Warren Gus D. , Phillips Sophia R. , Connor Patrick J. , Marqusee Susan , Harms Michael J.
Published: October 2022

Stability constrains evolution. While much is known about constraints on destabilizing mutations, less is known about the constraints on stabilizing mutations. We recently identified a mutation in the innate immune protein S100A9 that provides insight into such constraints. When introduced into human S100A9, M63F simultaneously increases the stability of the protein and disrupts its natural ability to activate Toll-like receptor 4. Using chemical denaturation, we found that M63F stabilizes a calcium-bound conformation of hS100A9. We then used NMR to solve the structure of the mutant protein, revealing that the mutation distorts the hydrophobic binding surface of hS100A9, explaining its deleterious effect on function. Hydrogen–deuterium exchange (HDX) experiments revealed stabilization of the region around M63F in the structure, notably Phe37. In the structure of the M63F mutant, the Phe37 and Phe63 sidechains are in contact, plausibly forming an edge-face π-stack. Mutating Phe37 to Leu abolished the stabilizing effect of M63F as probed by both chemical denaturation and HDX. It also restored the biological activity of S100A9 disrupted by M63F. These findings reveal that Phe63 creates a molecular staple with Phe37 that stabilizes a nonfunctional conformation of the protein, thus disrupting function. Using a bioinformatic analysis, we found that S100A9 proteins from different organisms rarely have Phe at both positions 37 and 63, suggesting that avoiding a pathological stabilizing interaction indeed constrains S100A9 evolution. This work highlights an important evolutionary constraint on stabilizing mutations, namely, that they must avoid inappropriately stabilizing nonfunctional protein conformations.
Elucidation of the physical factors that control activated transport of penetrants in chemically complex glass-forming liquids
Authors: Mei Baicheng , Sheridan Grant S. , Evans Christopher M. , Schweizer Kenneth S.
Published: October 2022

Understanding the activated transport of penetrant or tracer atoms and molecules in condensed phases is a challenging problem in chemistry, materials science, physics, and biophysics. Many angstrom- and nanometer-scale features enter due to the highly variable shape, size, interaction, and conformational flexibility of the penetrant and matrix species, leading to a dramatic diversity of penetrant dynamics. Based on a minimalist model of a spherical penetrant in equilibrated dense matrices of hard spheres, a recent microscopic theory that relates hopping transport to local structure has predicted a novel correlation between penetrant diffusivity and the matrix thermodynamic dimensionless compressibility,S0(T) (which also quantifies the amplitude of long wavelength density fluctuations), as a consequence of a fundamental statistical mechanical relationship between structure and thermodynamics. Moreover, the penetrant activation barrier is predicted to have a factorized/multiplicative form, scaling as the product of an inverse power law ofS0(T) and a linear/logarithmic function of the penetrant-to-matrix size ratio. This implies an enormous reduction in chemical complexity that is verified based solely on experimental data for diverse classes of chemically complex penetrants dissolved in molecular and polymeric liquids over a wide range of temperatures down to the kinetic glass transition. The predicted corollary that the penetrant diffusion constant decreases exponentially with inverse temperature raised to an exponent determined solely by howS0(T) decreases with cooling is also verified experimentally. Our findings are relevant to fundamental questions in glassy dynamics, self-averaging of angstrom-scale chemical features, and applications such as membrane separations, barrier coatings, drug delivery, and self-healing.
Masks as a moral symbol: Masks reduce wearers’ deviant behavior in China during COVID-19
Authors: Lu Jackson G. , Song Lesley Luyang , Zheng Yuhuang , Wang Laura Changlan
Published: October 2022

Since the outbreak of COVID-19, mask wearing has become a global phenomenon. How do masks influence wearers’ behavior in everyday life? We examine the effect of masks on wearers’ deviant behavior in China, where mask wearing is mostly a public-health issue rather than a political issue. Drawing on behavioral ethics research, we test two competing hypotheses: (a) masks disinhibit wearers’ deviant behavior by increasing their sense of anonymity and (b) masks are a moral symbol that reduces wearers’ deviant behavior by heightening their moral awareness. The latter hypothesis was consistently supported by 10 studies (including direct replications) using mixed methods (e.g., traffic camera recording analysis, observational field studies, experiments, and natural field experiment) and different measures of deviant behavior (e.g., running a red light, bike parking in no-parking zones, cheating for money, and deviant behavior in the library). Our research (
n
= 68,243) is among the first to uncover the psychological and behavioral consequences of mask wearing beyond its health benefits.
Pelagic seabirds reduce risk by flying into the eye of the storm
Authors: Lempidakis Emmanouil , Shepard Emily L. C. , Ross Andrew N. , Matsumoto Sakiko , Koyama Shiho , Takeuchi Ichiro , Yoda Ken
Published: October 2022

Cyclones can cause mass mortality of seabirds, sometimes wrecking thousands of individuals. The few studies to track pelagic seabirds during cyclones show they tend to circumnavigate the strongest winds. We tracked adult shearwaters in the Sea of Japan over 11 y and found that the response to cyclones varied according to the wind speed and direction. In strong winds, birds that were sandwiched between the storm and mainland Japan flew away from land and toward the eye of the storm, flying within ≤30 km of the eye and tracking it for up to 8 h. This exposed shearwaters to some of the highest wind speeds near the eye wall (≤21 m s–1) but enabled them to avoid strong onshore winds in the storm’s wake. Extreme winds may therefore become a threat when an inability to compensate for drift could lead to forced landings and collisions. Birds may need to know where land is in order to avoid it. This provides additional selective pressure for a map sense and could explain why juvenile shearwaters, which lack a map sense, instead navigating using a compass heading, are susceptible to being wrecked. We suggest that the ability to respond to storms is influenced by both flight and navigational capacities. This may become increasingly pertinent due to changes in extreme weather patterns.
Constructionalized rhetorical questions from negatively biased to negation polarity
Authors: Bardenstein Ruti
Published: October 2022

How does a rhetorical question become an adverbialnpidown-toner? This paper focusses on a specific type of grammaticalization process: the grammaticalization of a rhetorical constructionà laGoldberg (1995), namely, a “constructionalized rhetorical question” (Bardenstein 2018) which turns into a down-toning adverbial. The particular focus of this paper is on the Hebrewlo mi yodea ma(‘not who knows what’; i.e., ‘not of high quality/quantity’) which has developed from the constructionalization of two earlier constructions. Initially, the biblical question-phrasemi yodea(‘who knows’) constructionalized as “negatively biased” (Ladusaw 1996). This is a rhetorical question, to which the obvious answer is negative, and in our casemi yodeacan be interpreted as ‘nobody knows’. Most often, it is the case of “not knowing” what the future holds. Then, once a direct objectma(‘what’) was added, it constructionalized once again into a strengthening/ intensification constructionmi yodea ma(‘who knows what’), conveying high quantity/quality. This happened since “not knowing what is to happen” can be interpreted as “anything can happen” and this interpretation was used rhetorically to strengthen one‘s utterance. Lastly,mi yodea ma(‘who knows what’) constructionalized under the scope of the negation operatorlo(‘not’), into a versatile down-toning adverbial:lo mi yodea ma. Since it is very difficult to negate a strongly positive construction without implying that a less positive one is to some extent true, this negated construction became a versatile down-toner.
Power dynamics and pragma-cultural sources of unsourced evidentiality in Persian
Authors: Zaini Amin , Shokouhi Hossein
Published: October 2022

This paper investigates participants’ reflections on power relations embedded in the cultural-pragmatics of
unsourced evidentials in Persian texts. Using Fairclough’s (2013) critical discourse
analysis, we adopted Hanks’ (2018) ethnography of referential practices and Foucault’s (1980) power dynamics to analyse 16 Persian texts through follow up interviews
and focus group discussions on two opposing pairs of texts – one pair on Iranian national identity versus Persian literature, and
another on Iranian politics versus religion. Our analysis revealed that unsourced evidentials appear in Persian predominantly due
to censorship and sometimes due to deliberate use by authors (e.g., for winning an argument). Text consumers often overlook
unsourced evidentials while reflecting on politico-religious referents, such as inequalities and bigotry. This has roots in
Persian literature, religion, and politics of power embedded in the culture, and the participants’ attention to inequalities and
discriminations has roots in referential practices in current Iranian discourse.
Terminological problems of terminology users
Authors: Žagar Karer Mojca , Fajfar Tanja
Published: October 2022

Terminological counselling is ad hoc terminology work that provides the terminology user with a relatively quick
and credible answer to a terminological question. In this article, we present the Terminological Counselling Service offered by
the Terminology Section of the ZRC SAZU Fran Ramovš Institute of the Slovenian Language since 2013. Through a web form, users
submit a question, which is answered by five terminologists in a joint opinion. For this article, all 75 questions received by the
Terminological Counselling Service in 2020 were examined. They were analysed in terms of the subject fields in which the users
have terminological problems, the institutions the users are affiliated with, and the content of the questions. We believe that
the Terminological Counselling Service plays an important role, as the number of users is increasing year by year.
Mn substitution in the topological metal Zr2Te2P
Authors: Oladehin O , Feng K , Haddock J W , Galeano-Cabral J , Wei K , Xin Y , Latturner S E , Baumbach R E
Published: October 2022

Results are reported for Mn intercalated Zr2Te2P, where x-ray diffraction , energy dispersive spectroscopy, and transmission electron microscopy measurements reveal that the van der Waals bonded Te–Te layers are partially filled by Zr and Mn ions. This leads to the chemical formulas Zr0.07Zr2Te2P and Mn0.06Zr0.03Zr2Te2P for the parent and substituted compounds, respectively. The impact of the Mn ions is seen in the anisotropic magnetic susceptibility, where Curie–Weiss fits to the data indicate that the Mn ions are in the divalent state. Heat capacity and electrical transport measurements reveal metallic behavior, but the electronic coefficient of the heat capacity (γ
Mn ≈ 36.6 mJ (mol·K2)−1) is enhanced by comparison to that of the parent compound. Magnetic ordering is seen at

T

M

≈
4

 K, where heat capacity measurements additionally show that the phase transition is broad, likely due to the disordered Mn distribution. This transition also strongly reduces the electronic scattering seen in the normalized electrical resistance. These results show that Mn substitution simultaneously introduces magnetic interactions and tunes the electronic state, which improves prospects for inducing novel behavior in Zr2Te2P and the broader family of ternary tetradymites.
Mangasese doped polypyrole nanoparticels for photothermal/chemodynamic therapy and immune activation
Authors: Li Zhuoxin , Zhou Lingyi , Qin Yuyan , Sun Xin , Li Qianzhe , Yang Mengyu , Yu Beibei , Du Fengyi , Zhang Miaomiao
Published: October 2022

Photothermal therapy (PTT) is a promising treatment that efficiently suppresses local cancer, but fails to induce a robust antitumor immune response against tumor metastasis and recurrence. In this study, a NIR responsive nano-immunostimulant (Mn/A-HP NI) is fabricated by entrapping manganese and azo-initiator (AIPH) into hyaluronic acid-based polypyrrole nanoparticle. The as-prepared Mn/A-HP NIs with a high photothermal conversion efficiencey of 20.17% dramatically induced the imunogenic cell death of tumor cells and triggered the release ATP and HMGB1. Meanwhile, the hyperthermia induced AIPH decomposition to produce alkyl radicals which further destroyed cancer cells. Furthermore, the Mn/A-HP NIs were capable of promoting the maturation and antigen cross-presentation ability of dendritic cells. Consequently, the multifunctional Mn/A-HP NIs provided a combined treatment via integrating PTT/chemo-dynamic therapy and immune activation for tumor therapy.
Measurements and interpretation of EEDF in a discharge with a hollow cathode in helium: effect of the measuring probe and the anode on the form of the distribution function
Authors: Andreev S N , Bernatskiy A V , Dyatko N A , Kochetov I V , Ochkin V N
Published: October 2022

Experimental and theoretical studies of the electron energy distribution function in hollow cathode discharge plasma have been carried out. The discharge was ignited in helium at a pressure of 0.75 Torr, and the distance between the rectangular hollow cathode and anode was 3 cm. The measurements were performed using the probe method at various distances from the anode. The obtained distribution functions turned out to be strongly depleted in low-energy electrons. As applied to the experimental conditions, the role of two effects that can lead to such depletion was analyzed: instrumental distortions of the distribution function due to the electron sink on the probe and the absorption of electrons by the anode. According to the calculations, under the considered conditions, the main contribution to the depletion of the measured distribution functions by the slow electrons comes from the second effect.
Formations of anode double layer and ion beam in bipolar-pulse HiPIMS (BP-HiPIMS)
Authors: Han Mingyue , Luo Yang , Li Hua , Tang Ling , Li Duoduo , Gu Jiabin , Li Liuhe , Xu Ye , Luo Sida
Published: October 2022

As an emerging ion acceleration plasma source, the bipolar-pulse high power impulse magnetron sputtering (BP-HiPIMS) discharge provides an effective approach to improve deposited ion energy and tailor the film properties for a large range of applications. The ion acceleration mechanism in BP-HiPIMS discharge is very vital but still unclear now. In the present work, the ion acceleration mechanism is systematically investigated via the experimental measurements, particle-in-cell/Monte Carlo collision (PIC-MCC) simulation, and theoretical model together. In the experiment part, the floating potential V
f and the ion velocity distribution function (IVDF) have been measured via the Langmuir probe and the retarding field energy analyser (RFEA) respectively. The measurements show that the V
f at the downstream drops from +80 V to ∼+40 V after applying the positive pulse for ∼75 μs, suggesting the formation of the double layer. Correspondingly, the IVDF changes from the unimodal Maxwellian distribution to the bimodal distribution, suggesting the existence of the ion beam. The PIC-MCC simulation results clearly show the development process of the double layer and ion beam. A theoretical model is introduced to explore the complex plasma dynamics in the experiment and simulation. The theoretical results illustrate that (i) the sheath in front of the target surface prefers an ion sheath rather than an electron sheath, (ii) the stable position of the double layer boundary is in the magnetic null point, (iii) the potential drop across the boundary is influenced by the gas pressure p. These important theoretical results are well consistent with the measurements and simulation. In addition, the oscillation of the double layer boundary and the instabilities of the ions are briefly discussed by combining the previous works.
The multipole resonance probe: simultaneous determination of electron density and electron temperature using spectral kinetic simulation
Authors: Gong Junbo , Friedrichs Michael , Oberrath Jens , Brinkmann Ralf Peter
Published: October 2022

The multipole resonance probe (MRP) is an innovative sensor suitable for monitoring and control of industrial plasma processes. It is a realization of ‘active plasma resonance spectroscopy’, a class of electromagnetic diagnostic methods which employ the ability of plasmas to resonate on or near the plasma frequency. A signal in the GHz range is fed to the plasma via an electrical probe; the spectral response S(ω) is recorded, and then evaluated with a mathematical model to obtain information on the internal plasma parameters. In this study, a spectral kinetic model of the MRP is discussed. It is superior to previous analyses based on the Drude model, as it allows to determine not only the electron density n
e but also the electron temperature T
e from S(ω). Good agreement with independent measurements shows the suitability of the model.
Data-driven Seeing Prediction for Optics Telescope: from Statistical Modeling, Machine Learning to Deep Learning Techniques
Authors: Ni Wei-Jian , Shen Quan-Le , Zeng Qing-Tian , Wang Huai-Qing , Cui Xiang-Qun , Liu Tong
Published: October 2022

Predicting seeing of astronomical observations can provide hints of the quality of optical imaging in the near future, and facilitate flexible scheduling of observation tasks to maximize the use of astronomical observatories. Traditional approaches to seeing prediction mostly rely on regional weather models to capture the in-dome optical turbulence patterns. Thanks to the developing of data gathering and aggregation facilities of astronomical observatories in recent years, data-driven approaches are becoming increasingly feasible and attractive to predict astronomical seeing. This paper systematically investigates data-driven approaches to seeing prediction by leveraging various big data techniques, from traditional statistical modeling, machine learning to new emerging deep learning methods, on the monitoring data of the Large sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST). The raw monitoring data are preprocessed to allow for big data modeling. Then we formulate the seeing prediction task under each type of modeling framework and develop seeing prediction models through using representative big data techniques, including ARIMA and Prophet for statistical modeling, MLP and XGBoost for machine learning, and LSTM, GRU and Transformer for deep learning. We perform empirical studies on the developed models with a variety of feature configurations, yielding notable insights into the applicability of big data techniques to the seeing prediction task.
Detecting the locus of auditory attention based on the spectro-spatial-temporal analysis of EEG
Authors: Jiang Yifan , Chen Ning , Jin Jing
Published: October 2022

Objective. Auditory attention decoding (AAD) determines which speaker the listener is focusing on by analyzing his/her EEG. Convolutional neural network (CNN) was adopted to extract spectro-spatial-feature (SSF) from short-time-interval of EEG to detect auditory spatial attention without stimuli. However, the following factors are not considered in SSF-CNN scheme. (a) Single-band frequency analysis cannot represent the EEG pattern precisely. (b) The power cannot represent the EEG feature related to the dynamic patterns of the attended auditory stimulus. (c) The temporal feature of EEG representing the relationship between EEG and attended stimulus is not extracted. To solve these problems, SSF-CNN scheme was modified. Approach. (a) Multiple-frequency bands, but not a single alpha frequency band, of EEG, were analyzed to represent the EEG pattern more precisely. (b) Differential entropy, but not power, was extracted from each frequency band to represent the disorder degree of EEG, which was related to the dynamic patterns of the attended auditory stimulus. (c) CNN and convolutional-long-short-term-memory (ConvLSTM) were combined to extract spectro-spatial-temporal features from the 3D descriptor sequence constructed based on the topographical activity maps of multiple-frequency bands. Main results. Experimental results on KUL, DTU, and PKU with 0.1 s, 1 s, 2 s, and 5 s decision windows demonstrated that: (a) The proposed model outperformed SSF-CNN and state-of-the-art AAD models. Specifically, when the auditory stimulus was unavailable, AAD accuracy could be enhanced by at least

3.25
%

,

3.96
%

and

5.08
%

on KUL, DTU, and PKU, respectively, compared with the baselines. And, on KUL, the longer decision window corresponded to lower enhancement, while on both DTU and PKU, the longer decision window corresponded to higher enhancement, except for two cases when decision window length was 2 s on PKU or 5 s on DTU. (b) Each modification contributed to the performance enhancement. Significance. DE feature, multi-band frequency analysis, and ConvLSTM-based temporal analysis help to enhance AAD accuracy.
A slice-test demonstrator for the upgrade of the CMS drift tubes at High-Luminosity LHC
Authors: Battilana C.
Published: October 2022

Drift Tubes (DT) detectors equip the CMS muon system barrel region serving both as offline tracking and triggering devices. Existing DT chambers will operate throughout High-Luminosity LHC, but, in order to withstand event rates and integrated doses far beyond the initial design specification, an upgrade of the current readout and trigger electronics is planned. In the upgraded system, time-to-digital converters will stream hits to new back-end boards that, beyond event matching, will perform online tracking of trigger segments exploiting the ultimate DT cell resolution. During the second LHC long shutdown, prototypes of the aforementioned electronics were installed in four DT chambers with the same azimuthal acceptance, instrumenting a demonstrator of the HL-LHC DT upgrade (DT slice-test). In this report, the motivation for such an upgrade will be highlighted, and the status of the DT slice-test operation, as well as its performance measured with cosmic muons, will be presented. Plans towards future developments of the demonstrator throughout the LHC Run-3 will also be discussed.
A 64-channel high-time resolution digital waveform sampling electronic system based on DRS4 for positron burst annihilation lifetime measurement
Authors: Wang M. , Bian Z. , Wang Y. , Li D. , Li X. , Cai J. , Wang P. , Wang B. , Cao X. , Zhang Z. , Kuang P. , Liu F. , Zhang H. , Yu X. , Chen T. , Yun X. , Wei L.
Published: October 2022

Measurements of the positron burst annihilation lifetime place high demand on the time discrimination of electronics. DRS4 chips based on switched capacitor array technology (SCA) are used to develop an electronic system with a total (2048 + 256)-channel sampling rate up to 5.12 GSPS, which can provide better time resolution and flexible data processing. The electronic system is modular in design and includes a front-end waveform sampling module (WSM) with 32 waveform sampling boards, each with 64 input channels plus 8 additional channels(one per DRS4 chip) for time calibaion, in addition to a back-end data processing module (DPM). The fan-out circuit integrated with the DPM will fan out the T0 signal in multiple stages at the time of positron burst generation and provide a common starting time and trigger signal for every DRS4 chip in the WSM. In this electronic system, the jitter of T0 after three-stage fan-out is 18 ps. After DC offset correction and time interval nonuniformity calibration, the coincidence time resolution with other channels is about 21 ps (σ). In addition, we correct the time difference of different channels of different chips, which is caused by different trace lengths of the multi-level fan-out T0 signal and the different fabrication processes. The electronic system is used to evaluate a 64-pixel detector module, and the time resolution of the detection module is measured to be 44 ps (σ).
Macroscopic fluctuations of a driven tracer in the symmetric exclusion process
Authors: Dandekar Rahul , Mallick Kirone
Published: October 2022

The dynamics of an asymmetric tracer in the symmetric simple exclusion process (SEP) is mapped, in the continuous scaling limit, to the local current through the origin in the zero-range process with a biased bond. This allows us to study the hydrodynamics of the SEP with an asymmetric tracer with a step initial condition, leading to the average displacement as a function of the bias and the densities on both sides. We then derive the cumulant generating function of the process in the high-density limit, by using the macroscopic fluctuation theory and obtain agreement with the microscopic results of Poncet et al (2021). For more general initial conditions, we show that the tracer variance in the high-density limit depends only on the generalized susceptibility in the initial condition.
One-pot ultrasonicated synthesized lead-less hybrid perovskite nanocrystals: structural, morphological and optical analysis
Authors: Singh Rajan Kumar , Gouraha Sourabh , Singh Anupriya , Jain Neha , Singh Jai
Published: October 2022

In contemporary years, hybrid lead halide perovskites nanocrystals (HPNCs) have emerged as core materials for low-cost solution-processable photovoltaic, light-emitting devices as well as in other optoelectronic fields, such as high-efficiency perovskite fluorescent quantum dots (quantum dot, QD). Although the high efficiency makes them an attractive active material, reducing the Pb-toxicity and enhancing the stability while sustaining the efficiency of the HPNCs devices is important for their successful commercialization in future. Here, we report for the first time the fabrication of excellent quality Pb-less, MAPb1-x
Sn
x
Br3 (x = 0 to 0.50) perovskite NCs by one-pot ultrasonication method. Interestingly, an outstanding photoluminescence quantum yield (PLQY) of 94% and better lifetime performance than 100% Pb-based HPNCs is obtained for Pb-less HPNCs. The successful incorporation of Sn MAPb1-x
Sn
x
Br3 HPNCs is confirmed by energy-dispersive x-ray (EDX) and x-ray photoelectron spectroscopy (XPS) analysis. Although the particle size for Pb-less HPNCs was different, the change in morphology and structure was minimal as confirmed by transmission electron microscopy (TEM) analysis. The optical analysis indicated bandgap tuning, which is evident by the blue shift of the band edge in absorbance spectra and photoluminescence peak after incorporating Sn2+. To the best of our knowledge, this is the highest achieved PLQY for Sn-substituted hybrid Pb-based HPNCs. The synthesis by using one pot ultrasonication method might be helpful for large-scale HPNCs production and can pave the way for future research on less-toxic and stable alternatives to Pb-based HPNCs.
Investigation of friction welding parameters of AISI 304L/Ti-6AL-4V joints
Authors: Kumar R Ramesh , Babu J M , Saleh Bahaa , Chandrashekar A , Saxena Kuldeep K , Deepak A , Razak Abdul , Buradi Abdulrajak , Ketema Abiot
Published: October 2022

The present paper focuses on evaluating the bonding strength interfaces between the contact materials such as AISI 304L and Ti-6Al-4V via. the friction welding (FW). Experimental tests are performed by considering the process parameters such as friction time, rotational speed and friction pressure, mechanical properties were evaluated. The rotational speed of 1800, 1600, 2100, 2300 and 2500 rpm were considered in the study. The response surface methodology (RSM) is used to predict the outcomes of the work. Experimental tests were revealed that the friction pressure of 160 MPa, 7 sec of friction time and speed of 2300rpm are the optimal parameters based on the joint strength. Also, observed that the aluminum interlayer thickness of 1.25 μm on the Ti-6Al-4V side and 1.38 μm on the AISI 304L side. The tensile strength of 143.39 MPa was noticed at the interface area. The RSM response generates the curved potential line frequency range with 6.5% elongations. Results confirm that, the response surface methodology outcomes and experimental values were in close agreement.
Enhancement of infrared shielding property of SnO2 using Sb as a dopant
Authors: Ahmad Towseef , Ansari Mohd Zubair
Published: October 2022

Transparent conducting oxides (TCO) are essential to the operation of advanced energy harvesting and storage devices, as well as display technology. Doped tin oxide (SnO2) exhibits enhanced optical and thermal characteristics in comparison to undoped SnO2. In this article, the cost-effective sol-gel methodology was employed in the synthesis of tin oxide (SnO2) and antimony (Sb) doped tin oxide nanoparticles. According to the XRD analysis, the tetragonal structure was maintained despite the apparent reduction in crystal size as the amount of Sb increased. In the study, the effect that Sb doping has on absorption and reflection in the visible and near-infrared regions was analyzed. The band gap of the nanoparticles was observed to broaden as the concentration of Sb doping was increased from 3.44 eV (ATO-0) to 4.62 eV (ATO-6). The results from UV–vis-NIR spectra demonstrated that the ATO films efficiently reduced the amount of infrared light that passed through them. The results of the heat-insulation test showed that ATO-coated glass outperformed uncoated glass in terms of heat insulation. Because of these characteristics, ATO could be a good replacement material, especially for solar cells and smart windows.
MoS2/TiO2 van der Waals heterostructures for promising photocatalytic performance: a first-principles study
Authors: Tang Yu , Liu Qin , Lei Jiehong , Zhang Min , Yang Hui , Duan Meihong , Ma Xiaoyang , Song Tingting
Published: October 2022

Heterostructures have attracted extensive attention due to their van der Waals interactions between layers. The photocatalysts of Two-dimensional (2D) heterostructure based on MoS2 have tempted more and more attention because of their eminent photocatalytic performance, but they are still limited by the weak absorption of visible light and lesser conversion efficiency of solar-to-hydrogen. In this work, we exhaustively investigate the electronic, optical and the structural properties of 2D MoS2/TiO2 heterostructures by using first-principles calculations. The result shows that both MoS2/TiO2(100) and MoS2/TiO2(001) heterostructures are stable interfaces and direct Z-scheme photocatalysts, which is favourable for the separation and migration of electron and hole pairs under the excitation of light. And what’s more, both the MoS2/TiO2(100) and MoS2/TiO2(001) heterostructures exhibit direct band gap at the Γ point, this is conductive to better electronic transition and absorption of light because of lower energy depletion than indirect band gap semiconductors. The relatively small band gap (1.08 eV of MoS2/TiO2(001) and 0.52 eV of MoS2/TiO2(100)) cause the entire visible light region can be covered by the light absorption spectrum. The result is that building heterostructures of TiO2 with MoS2 advances the absorption of light and hastens the separation and migration of electron and hole pairs, the activity of photocatalysis could be advanced by all of these. The results provide a basis of heterostructure photocatalysts based on monolayer MoS2 and deep comprehension of their physical mechanism.
Real-World Trends in the Evaluation of Medical Products
Authors: Hennessy Sean , Berlin Jesse A
Published: October 2022

There is a compelling need to evaluate the real-world health effects of medical products outside of tightly controlled preapproval clinical trials. This is done through pharmacoepidemiology, which is the study of the health effects of medical products (including drugs, biologicals, and medical devices and diagnostics) in populations, often using nonrandomized designs. Recent developments in pharmacoepidemiology span changes in the focus of research questions, research designs, data used, and statistical analysis methods. Developments in these areas are thought to improve the value of the evidence produced by such studies, and are prompting greater use of real-world evidence to inform clinical, regulatory, and reimbursement decisions.