bluuebunny/crossref_metadata_2025 huggingface dataset:
The merit of pressure dependent kinetic modelling in steam cracking
Authors: Aerssens Jeroen , Vermeire Florence , Aravindakshan Syam Ukkandath , Van de Vijver Ruben , Van Geem Kevin M.
Published: March 2022

Modelling case study on the role of pressure dependence in single event kinetic modelling for steam cracking of both ethane and propane. Results are validated with in-house generated experimental data.
Dual enzyme co-immobilization on reversibly soluble polymers for the one-pot conversion of ferulic acid from wheat bran
Authors: Wang Kaipeng , Jin Wenbin , Ding Yiling , Lyu Yongmei , Liu Jinbin , Yu Xiaohong
Published: March 2022

Feruloyl esterase and xylanase were covalently co-immobilized onto a reversible soluble carrier Eudragit L-100.
Assessment of time-dependent density functionals for the electronic excitation energies of organic dyes used in DSSCs
Authors: Alkhatib Qabas , Helal Wissam , Afaneh Akef T.
Published: March 2022

The absorption spectra modeled as the vertical excitation energies of 13 dye sensitizers used in dye-sensitized solar cells (DSSCs) are benchmarked by means of time-dependent (TD)-DFT, using 36 functionals from different DFT rungs.
Magnesene: a theoretical prediction of a metallic, fast, high-capacity, and reversible anode material for sodium-ion batteries
Authors: Ye Xiao-Juan , Li Tian-Kai , He Jing-Jing , Wang Xiang-Fu , Liu Chun-Sheng
Published: March 2022

We predict a two-dimensional Mg material (named magnesene) as an anode material for SIBs with intrinsic metallicity, high reversible capacity, and high ionic diffusivity.
LMAN1–MCFD2 complex is a cargo receptor for the ER-Golgi transport of α1-antitrypsin
Authors: Zhang Yuan , Zhu Min , Zheng Chunlei , Wei Wei , Emmer Brian T. , Zhang Bin
Published: March 2022

α1-antitrypsin (AAT) is a serine protease inhibitor synthesized in hepatocytes and protects the lung from damage by neutrophil elastase. AAT gene mutations result in AAT deficiency (AATD), which leads to lung and liver diseases. The AAT Z variant forms polymer within the endoplasmic reticulum (ER) of hepatocytes and results in reduction in AAT secretion and severe disease. Previous studies demonstrated a secretion defect of AAT in LMAN1 deficient cells, and mild decreases in AAT levels in male LMAN1 and MCFD2 deficient mice. LMAN1 is a transmembrane lectin that forms a complex with a small soluble protein MCFD2. The LMAN1–MCFD2 protein complex cycles between the ER and the Golgi. Here, we report that LMAN1 and MCFD2 knockout (KO) HepG2 and HEK293T cells display reduced AAT secretion and elevated intracellular AAT levels due to a delayed ER-to-Golgi transport of AAT. Secretion defects in KO cells were rescued by wild-type LMAN1 or MCFD2, but not by mutant proteins. Elimination of the second glycosylation site of AAT abolished LMAN1 dependent secretion. Co-immunoprecipitation experiment in MCFD2 KO cells suggested that AAT interaction with LMAN1 is independent of MCFD2. Furthermore, our results suggest that secretion of the Z variant, both monomers and polymers, is also LMAN1-dependent. Results provide direct evidence supporting that the LMAN1–MCFD2 complex is a cargo receptor for the ER-to-Golgi transport of AAT and that interactions of LMAN1 with an N-glycan of AAT is critical for this process. These results have implications in production of recombinant AAT and in developing treatments for AATD patients.
Images2Poem in different contexts with Dual‐CharRNN
Authors: Yan Jie , Xie Yuxiang , Luan Xidao
Published: March 2022

Image to caption has attracted extensive research attention recently. However, image to poetry, especially Chinese classical poetry, is much more challenging. Previous works mainly focus on generating coherent poetry without taking the contexts of poetry into account. In this paper, we propose an Images2Poem with the Dual‐CharRNN model which exploits images to generate Chinese classical poems in different contexts. Specifically, we first extract a few keywords representing elements from the given image based on multi‐label image classification. Then, these keywords are expanded to related ones with the planning‐based model. Finally, we employ Dual‐CharRNN to generate Chinese classical poetry in different contexts. A comprehensive evaluation of human judgements demonstrates that our model achieves promising performance and is effective in enhancing poetry's semantic consistency, readability, and aesthetics. We present an Images2Poem with the Dual‐CharRNN model exploiting images to generate Chinese classical poems in different contexts, which effectively improves the semantic consistency, readability and aesthetics of the generated poetry.
A novel digital‐signal‐processor‐based maximum‐power‐point tracking control design for a vertical‐axis wind‐turbine generation system using neural network compensator
Authors: Tsai Ming‐Fa , Tseng Chung‐Shi , Hung Yu‐Hsiang , Tsai Kuo‐Lung
Published: March 2022

This paper presents a novel maximum‐power‐point tracking algorithm of a vertical‐axis wind‐turbine (VAWT) generation system using neural network compensator on the basis of a digital signal processing chip. First, the mechanical power versus rotation‐speed curve of a 3‐kW VAWT generator was constructed by means of the measurement data in various wind speeds. Because the slope of the wind‐turbine output power is a non‐linear function of the generator output current, air density, wind speed, and the characteristics of the wind‐turbine generator, the analytic solution for the maximum power is difficult to obtain due to its complexity, nonlinearity, and uncertainties of parameters. The innovation of this study is to obtain the maximum power of the wind‐turbine system using a recurrent neural network (RNN) by transferring the maximum‐power‐point tracking problem into a unit‐step‐command regulation problem despite the variation of the wind speed, ambient air density, and the load electrical characteristics. The uncertainties in the system are compensated by the RNN, which is composed of three‐layer networks with three neurons and feedback loops in the hidden layer for capturing the characteristics of the wind‐turbine generator system. Without the necessity of wind speed sensor, it only needs the generator output current and rotation speed as the inputs of the input layer. This structure containing only six neurons totally is simpler than the existing work. The duty cycle of the boost converter is determined by a proportional‐integral controller, the parameters of which are determined via a genetic algorithm by the minimisation of a performance index function with the help of MATLAB simulation tool. From the simulation and experimental results, the validity of the proposed control scheme was verified under various wind speed conditions. The performance efficiency and the tip speed ratio in each case of the experiment is near the optimal values of 0.28 and 4.3, respectively. The output power achieves 2048.4 W at the wind speed of 11 m/s in the steady state.
The influences of substrates' physical properties on enzymatic PET hydrolysis: Implications for PET hydrolase engineering
Authors: Pasula Rupali Reddy , Lim Sierin , Ghadessy Farid J. , Sana Barindra
Published: March 2022

Plastic pollution in diverse terrestrial and marine environments is a widely recognised and growing problem. Bio‐recycling and upcycling of plastic waste is a potential solution to plastic pollution, as these processes convert plastic waste into useful materials. Polyethylene terephthalate (PET) is the most abundant plastic waste, and this material can be degraded by a class of recently discovered bacterial esterase enzymes known as PET hydrolases (PETase). Investigations of the enzymatic hydrolysis of diverse PET molecules have clearly revealed that the biodegradability of various PET substrates depends on both their chemical structure and physical properties, including polymer length, crystallinity, glass transition temperature, surface area, and surface charge. This review summarises the known impacts of crystallinity and other physical properties on enzymatic PET hydrolysis.
Advanced distribution transformer asset management embracing its relocation: A cost saving approach
Authors: Azimi Hosseini Kamyar , Hajiaghapour‐Moghimi Mehran , Hajipour Ehsan , Vakilian Mehdi
Published: March 2022

Change in customers' consumption patterns due to the introduction of new electricity consuming technologies into human consumption practices has impacted the existing optimal loading profile of the grid facilities. Although some MV/LV distribution transformers (DTs) are operating under a light load profile, this does not guarantee that they are in a healthy condition, since necessary maintenance procedures are required. On the other hand, many unplanned overloading conditions occur on the other DTs and causes accelerated failures which contributes to very high operational costs. This paper presents the outcome of a study on how the planned DTs relocation can save asset managers against their huge DTs replacement costs developed due to the highly overloaded DTs failures in a utility, and how it will improve the overall reliability of the DTs. A mixed‐integer linear programming (MILP) solution is proposed to formulate the introduced economic relocation‐based asset management (AM) framework while minimizing total cost (TC) of the network. The results show that incorporating relocation techniques into the AM formulation ends in reduction of the distribution network TC and a decrease in asset failure rates if compared with application of traditional techniques.
Week‐ahead daily peak load forecasting using genetic algorithm‐based hybrid convolutional neural network
Authors: Hong Ying‐Yi , Chan Yu‐Hsuan , Cheng Yung‐Han , Lee Yih‐Der , Jiang Jheng‐Lun , Wang Shen‐Szu
Published: March 2022

Daily peak load forecasting is crucial for the operation of bulk power systems, including economic dispatch and unit commitment. It is also essential for peak load shaving and load management in distribution systems. In power markets, peak load forecasting helps participants develop bidding strategies. This paper proposes a new method, using a hybrid convolutional neural network (CNN) that is cascaded with a fully‐connected network, for making week‐ahead daily peak load forecasts. The proposed method uses three loops to obtain the optimal CNN: The outer loop performs crossover/mutation operations and tournament selection to produce chromosomes to optimize the network topology and hyperparameters (such as kernel size) of the hybrid CNN by genetic algorithms; the middle loop deals with the order of chromosomes; the inner loop optimizes the synaptic weights and parameters (e.g. values of a kernel) using Adam optimizer. Daily peak load data and corresponding meteorological data for Taiwan are explored. Simulation results show that the proposed method outperforms the traditional CNN, multi‐layer neural network, recurrent neural network, support vector regression and vector autoregressive moving average model.
The jump and stagnation of mass with speed
Authors: Dong Jun , Dong Na
Published: March 2022

In the general theory of relativity, the four‐dimensional space‐time of describing a mass body accelerated motion or in a gravitational field, although it is a curved Riemannian geometric space from the perspective of “integral geometry”, but for any instantaneous position of the moving mass body, there is a local Flat Space of Riemannian geometric space. The local Flat Space is a Mincowski space in which the inertial coordinate system can be used in the local small area. Between the proper coordinate systems of two interacting moving masses, or between a series of following proper coordinate systems experienced by a mass body moving in any way, there should be a coordinate transformation relationship similar to the traditional special theory of relativity. However, they have an important difference: in these instantaneous local inertial systems, the speed of light is no longer the constant c of vacuum, the effect of gravitational field or acceleration on the speed of light is the same as that of a medium with a dielectric constant of ε and a magnetic permeability of μ. Using the special theory of relativity with variable speed of light that the author has established can discuss relevant relativity physics issues in these instantaneous local inertial systems. This article uses the special theory of relativity with variable speed of light to derive the functional relationship between a moving mass and the change of speed. In addition to obtain the traditional continuous increasing function relationship, a step function relationship with stepped discontinuous changes is also obtained. At the same speed, the mass can have two values, such as a ladder upgrade one level; the same mass can be matched with two different speeds, such as one step extension forward on the same step stair. From the perspective of the increase in speed, the mass is stagnant on the step platform (the speed increases, the mass does not change), and it jumps in the step up ladder (the speed does not change, the mass has a jump change). This obviously incorporates the main image of quantum theory into the theory of relativity, which is the result that all physics researchers care about and expect.
The effect of different concentration of banana ambon puree on the physicochemical, microbiological, and organoleptic properties of rice bran yogurt
Authors: Iswanto Nathania , Srianta Ignatius , Noventia Poernomo Laurence , Nugerahani Ira , Kuswardhani Indah , Ristiarini Susana , Tewfik Ihab
Published: March 2022

The addition of Ambon Banana Puree (ABP) has potential to improve the functional and organoleptic properties of rice bran yogurt. Hence, this study was aim to determine the effect of different concentrations of ABP on physicochemical, microbiological, and organoleptic properties of rice bran yogurt. The latter was prepared with ABP at concentrations of 0%, 5%, 10%, 15%, 20%, and 25% (w/v) and each reproduced 4 (four) times. Different concentrations of ABP showed significant effect (P <0.05) on syneresis day 7, pH value, total LAB, and organoleptic of mouthfeel and appearance. Results highlighted that different ABP concentrations had no significant effect (P> 0.05) on syneresis day 0, total lactic acid of rice bran yogurt, and organoleptic property of taste. Based on these findings, rice bran yogurt with different concentrations of ABP had syneresis on day 0 was 0.089-0.500%, syneresis day 7 was 0.130-0.522 %, pH 4.349-4.593, and total lactic acid 0.9733%-1.0513%. Furthermore, organoleptic testing presenting the appearance preferences ranged from 2.15 to 6.07 (dislike-like), taste 4.10-4.78 (neutral-sufficient), and mouthfeel 3.65-5.53 (imperfect to like). The result of total LAB was 8.7335-9.1543 log cfu/g. ABP has a favourable effect on the physicochemical, microbiological, and organoleptic properties of rice bran yogurt.
Comparison of Proximate Analysis Value of Fresh Fruits and Vacuum Fried Fruit Chips
Authors: Saputri Annisa , Aminy Nuzul , Rahmadi Isnaini , Nasution Syahrizal , Mareta Dea Tio , Permana Lasuardi , Nurdin Samsu Udayana
Published: March 2022

Indigenous fruits such as bananas, jackfruit, and pineapple have sensory characteristics that many people like. However, these fresh fruits have a short shelf life. Processing Fruit chips using vacuum frying is one solution to extend the shelf life of fruit with good quality and nutrition content. This study aimed to obtain the proximate composition value of fresh fruit and vacuum fried fruit chips. The research method used proximate analysis based on water, carbohydrate, lipid, crude protein, crude fibre, and ash content. The results showed a significant difference in the water, carbohydrate, lipid, and ash content between fresh fruits and vacuum fried fruit chips. Meanwhile, in crude protein and crude fibre content, there was no significant difference. The water content of fresh fruits was higher than the vacuum-fried fruit chips. The carbohydrate, lipid, crude protein, and ash content of vacuum fried fruit chips were higher than the fresh fruits. The crude fibre of pineapple vacuum fried chips was higher than fresh pineapple. However, the crude fibre of fresh jackfruit and banana was higher than the vacuum fried fruit chips.
Recherche à usage dual sur les pathogènes modifiés en laboratoire
Authors: Velardo Fanny , Prudhomme Julie , Temime Laura , Jean Kévin
Published: March 2022

Les avancées techniques en biologie de synthèse rendent de plus en plus accessibles la modification ou même la fabrication de virus en laboratoire. Plusieurs travaux de recherche fondés sur la synthèse de pathogènes à potentiel pandémique ont créé la polémique au cours des années 2010 et, aujourd’hui encore, l’éventualité qu’une fuite de laboratoire soit à l’origine de la pandémie de Covid-19 fait débat. En France, un vide juridique subsiste concernant la synthèse de pathogènes modifiés. Une réflexion concertée vers un encadrement légal de ce type de recherche apparaît donc nécessaire et urgent pour que la recherche continue de représenter un bénéfice, plutôt qu’un risque, pour la société.
The role of the principle of inertia in KTAP models
Authors: Carbonaro Bruno
Published: March 2022

The mathematical models for describing the evolution of complex systems in the framework of the Kinetic Theory for Active Particles (KTAPs), based on suitable generalizations of Boltzmann’s kinetic theory of gases, nowadays seem to be the most versatile and effective ones to formulate in sufficiently precise and accurate terms, and possibly to solve, the most important and difficult problems not only of our everyday’s individual life but also of the life of human collectivities in the long term. In this connection, a simple examination of the application of KTAP to practical problems in which the state variables are not the usual position-velocity variables (and the kinetic state can, indeed, be completely disregarded), such as the prediction of the evolution of an epidemic in a given population in view of possible containment measures, suggests that the scheme is not always so general as it would be desirable for the simple reason that it is conditioned by the implicit (and natural) assumption of the principle of inertia, which in non-mechanical contexts should be rejected. Starting from this remark, this paper has a threefold aim: (1) to point out that KTAP equations make a tacit use of the principle of inertia; (2) to recall the reasons why the principle of inertia is naturally connected to the origin of KTAP models; and (3) to suggest a suitable modification of the KTAP general system, enabling the user to choose to adopt or reject the principle of inertia.
Band structure and polarization effects in photothermoelectric spectroscopy of a Bi2Se3 device
Authors: Pournia Seyyedesadaf , Jnawali Giriraj , Need Ryan F. , Jackson Howard E. , Wilson Stephen D. , Smith Leigh M.
Published: March 2022

Bi2Se3 is a prototypical topological insulator, which has a small bandgap (∼0.3 eV) and topologically protected conducting surface states. This material exhibits quite strong thermoelectric effects. Here, we show in a mechanically exfoliated thick (∼100 nm) nanoflake device that we can measure the energy dependent optical absorption through the photothermoelectric effect. Spectral signatures are seen for a number of optical transitions between the valence and conduction bands, including a broad peak at 1.5 eV, which is likely dominated by bulk band-to-band optical transitions but is at the same energy as the well-known optical transition between the two topologically protected conducting surface states. We also observe a surprising linear polarization dependence in the response of the device that reflects the influence of the metal contacts.
Ultrafast probing of plasma ion temperature in proton–boron fusion by nuclear resonance fluorescence emission spectroscopy
Authors: Qin T.-T. , Luo W. , Lan H.-Y. , Wang W.-M.
Published: March 2022

Aneutronic fusion reactions such as proton–boron fusion could efficiently produce clean energy with quite low neutron doses. However, as a consequence, conventional neutron spectral methods for diagnosing plasma ion temperature would no longer work. Therefore, finding a way to probe the ion temperature in aneutronic fusion plasmas is a crucial task. Here, we present a method to realize ultrafast in situ probing of 11B ion temperature for proton–boron fusion by Doppler broadening of the nuclear resonance fluorescence (NRF) emission spectrum. The NRF emission is excited by a collimated, intense γ-ray beam generated from submicrometer wires irradiated by a recently available petawatt (PW) laser pulse, where the γ-ray beam generation is calculated by three-dimensional particle-in-cell simulation. When the laser power is higher than 1 PW, five NRF signatures of a 11B plasma can be clearly identified with high-resolution γ-ray detectors, as shown by our Geant4 simulations. The correlation between the NRF peak width and 11B ion temperature is discussed, and it is found that NRF emission spectroscopy should be sensitive to 11B ion temperatures Ti > 2.4 keV. This probing method can also be extended to other neutron-free-fusion isotopes, such as 6Li and 15N.
Superconducting aluminum heat switch with 3 nΩ equivalent resistance
Authors: Butterworth James , Triqueneaux Sébastien , Midlik Šimon , Golokolenov Ilya , Gerardin Anne , Gandit Thibaut , Donnier-Valentin Guillaume , Goupy Johannes , Phuthi M. Keith , Schmoranzer David , Collin Eddy , Fefferman Andrew
Published: March 2022

Superconducting heat switches with extremely low normal state resistances are needed for constructing continuous nuclear demagnetization refrigerators with high cooling power. Aluminum is a suitable superconductor for the heat switch because of its high Debye temperature and its commercial availability in high purity. We have constructed a high quality Al heat switch whose design is significantly different than that of previous heat switches. In order to join the Al to Cu with low contact resistance, we plasma etched the Al to remove its oxide layer and then immediately deposited Au without breaking the vacuum of the e-beam evaporator. In the normal state of the heat switch, we measured a thermal conductance of 8T W/K2, which is equivalent to an electrical resistance of 3 nΩ according to the Wiedemann–Franz law. In the superconducting state, we measured a thermal conductance that is 2 × 106 times lower than that of the normal state at 50 mK.
Spintronic THz emitters based on transition metals and semi-metals/Pt multilayers
Authors: Hawecker J. , Rongione E. , Markou A. , Krishnia S. , Godel F. , Collin S. , Lebrun R. , Tignon J. , Mangeney J. , Boulier T. , George J.-M. , Felser C. , Jaffrès H. , Dhillon S.
Published: March 2022

Spintronic terahertz (THz) emitters based on the inverse spin Hall effect in ferromagnetic/heavy metal (FM/HM) heterostructures have become important sources for THz pulse generation. The design, materials, and control of these interfaces at the nanometer level have become vital to engineer their THz emission properties. In this work, we present studies of the optimization of such structures through a multi-pronged approach, taking advantage of material and interface engineering to enhance THz spintronic emission. This includes the application of multi-stacks of HM/FM junctions and their application to trilayer structures, the use of spin-sinks to simultaneously enhance the THz emitted fields and reduce the use of thick Pt layers to reduce optical absorption, and the use of semi-metals to increase the spin polarization and, thus, THz emission. Through these approaches, significant enhancements of the THz field can be achieved. Importantly, taking into account the optical absorption permits to elucidate novel phenomena such as the relation between the spin diffusion length and the spin-sink using THz spectroscopy, as well as possibly distinguishing between self- and interface-spin-to-charge conversion in semi-metals.
Stoichiometry-dependent surface electronic structure of SrTiO3 films grown by hybrid molecular beam epitaxy
Authors: Lee Dooyong , Liu Fengdeng , Truttmann Tristan K. , Chambers Scott A. , Jalan Bharat
Published: March 2022

We investigate the surface electronic structure of SrTiO3 (STO) films grown by a hybrid molecular beam epitaxy that are both stoichiometric and nonstoichiometric by means of x-ray photoelectron spectroscopy and electron energy loss spectroscopy. Increasing the fraction of the surface that is terminated with an SrO layer is correlated with a decrease in the chemical potential whereby the valence band maximum moves closer to the Fermi level, but without a significant change in the bandgap. Inasmuch as SrO-terminated STO (001) has previously been shown to act as an electron scavenger in which carriers from the bulk are trapped, we argue that the high fraction of SrO in the terminal layer is what lowers the chemical potential in Sr-rich STO. Our experimental results provide important insights into various physical phenomena that can occur on STO (001) surfaces and their effect on bulk electronic properties.
Distributed polarization-doped GaN p–n diodes with near-unity ideality factor and avalanche breakdown voltage of 1.25 kV
Authors: Nomoto Kazuki , Li Wenshen , Song Bo , Hu Zongyang , Zhu Mingda , Qi Meng , Protasenko Vladimir , Zhang Zexuan , Pan Ming , Gao Xiang , Marchand Hugues , Johnson Wayne , Jena Debdeep , Xing Huili Grace
Published: March 2022

Polarization-induced (Pi) distributed or bulk doping in GaN, with a zero dopant ionization energy, can reduce temperature or frequency dispersions in impurity-doped p–n junctions caused by the deep-acceptor-nature of Mg, thus offering GaN power devices promising prospects. Before comprehensively assessing the benefits of Pi-doping, ideal junction behaviors and high-voltage capabilities should be confirmed. In this work, we demonstrate near-ideal forward and reverse I–V characteristics in Pi-doped GaN power p–n diodes, which incorporates linearly graded, coherently strained AlGaN layers. Hall measurements show a net increase in the hole concentration of 8.9 × 1016 cm−3 in the p-layer as a result of the polarization charge. In the Pi-doped n-layer, a record-low electron concentration of 2.5 × 1016 cm−3 is realized due to the gradual grading of Al0-0.72GaN over 1 μm. The Pi-doped p–n diodes have an ideality factor as low as 1.1 and a 0.10 V higher turn-on voltage than the impurity-doped p–n diodes due to the increase in the bandgap at the junction edge. A differential specific on-resistance of 0.1 mΩ cm2 is extracted from the Pi-doped p–n diodes, similar with the impurity-doped counterpart. The Pi-doped diodes show an avalanche breakdown voltage of ∼1.25 kV, indicating a high reverse blocking capability even without an ideal edge-termination. This work confirms that distributed Pi-doping can be incorporated in high-voltage GaN power devices to increase hole concentrations while maintaining excellent junction properties.
Structural and thermal analysis of polycrystalline diamond thin film grown on GaN-on-SiC with an interlayer of 20 nm PECVD-SiN
Authors: Wu Mei , Cheng Ke , Yang Ling , Hou Bin , Zhang Xin-Chuang , Wang Ping , Zhang Meng , Zhu Qing , Zheng Xue-Feng , Hu Yan-Sheng , Ma Xiao-Hua , Hao Yue
Published: March 2022

A 1.5-μm polycrystalline diamond was deposited on the AlGaN/GaN heterojunction on the SiC substrate with a 20-nm SiN dielectric. A 4.9% increase in 2DEG density after the diamond growth due to the increase in tensile strain of the GaN layer is confirmed by micro-Raman measurements. The interfacial analysis through the transmission electron microscopy and electron energy loss spectroscopy shows a thickness reduction in the SiN layer of ∼1.7 nm, which converts to a thin SiC layer at the diamond/SiN interface, and no carbon diffusion is found in the SiN layer after the diamond growth. Device simulation using the thermal properties extracted by time domain thermoreflectance predicts a temperature drop of 17.1 °C when the diamond only covers the device access region and reveals that the improvement of thermal boundary resistance is much more effective than that of the diamond thermal conductivity for the top-side heat spreading, which is mainly due to the limited thickness of the top diamond film.
Optimal generation of delay-controlled few-cycle pulses for high harmonic generation in solids
Authors: Su Yabei , Fang Shaobo , Wang Shuai , Liang Yueying , Chang Guoqing , He Xinkui , Wei Zhiyi
Published: March 2022

Delay-controlled two-color, few-cycle pulses are powerful tools for ultrafast nonlinear optics. In this Letter, 35-fs, 800 nm pulses were injected into a noble-gas-filled hollow-core fiber to obtain over-octave spectra (450–1000 nm) and were divided into two parts for dispersion management by a Mach–Zehnder–type interferometer. Two few-cycle pulses with pulse widths of 9.3 and 4.5 fs were generated in the long-wavelength side and the short-wavelength side, respectively. The temporal profiles were measured as the function of the different delay between the two pulses. The shortest 3.6 fs, 0.75 mJ near-single-cycle pulses were synthesized at an optimal delay. The delay-controlled high-harmonic generation in MgO was experimentally demonstrated leading to twofold enhancement of high-order harmonic (HH) yields at 10.3 eV and the extension of HH frequency under time-delay modulation. This method provides an extensive way for manipulating delay-controlled multi-color pulses, which can be used for controlling ionization dynamics in extreme nonlinear optics. We believe that it will be a powerful tool for ultrafast science.
Machine learning investigation of viscosity and ionic conductivity of protic ionic liquids in water mixtures
Authors: Duong Dung Viet , Tran Hung-Vu , Pathirannahalage Sachini Kadaoluwa , Brown Stuart J. , Hassett Michael , Yalcin Dilek , Meftahi Nastaran , Christofferson Andrew J. , Greaves Tamar L. , Le Tu C.
Published: March 2022

Ionic liquids (ILs) are well classified as designer solvents based on the ease of tailoring their properties through modifying the chemical structure of the cation and anion. However, while many structure–property relationships have been developed, these generally only identify the most dominant trends. Here, we have used machine learning on existing experimental data to construct robust models to produce meaningful predictions across a broad range of cation and anion chemical structures. Specifically, we used previously collated experimental data for the viscosity and conductivity of protic ILs [T. L. Greaves and C. J. Drummond, Chem. Rev. 115, 11379–11448 (2015)] as the inputs for multiple linear regression and neural network models. These were then used to predict the properties of all 1827 possible cation–anion combinations (excluding the input combinations). These models included the effect of water content of up to 5 wt. %. A selection of ten new protic ILs was then prepared, which validated the usefulness of the models. Overall, this work shows that relatively sparse data can be used productively to predict physicochemical properties of vast arrays of ILs.
Pyroelectrics on purpose: A perspective on generation vs harvesting
Authors: Hanrahan Brendan , Smith Andrew , Bhatia Bikram
Published: March 2022

Solid-state pyroelectric heat engines that utilize the temperature and electric field dependence of electric displacement are promising for high-efficiency high-power thermal-to-electrical energy conversion. However, one of the key challenges for pyroelectric energy conversion is the inaccessibility of tunable transient heat sources for energy harvesting. This Perspective analyzes the potential of thermal waveform engineering for pyroelectric energy generation. We use the Landau-Devonshire phenomenological model to evaluate the energy conversion performance of a representative pyroelectric material coupled to (1) static heat source/sink via thermal switches, and (2) modulated heat source. Using this thermodynamic analysis, which accounts for thermal and electrical losses, we demonstrate a path toward maximizing pyroelectric energy conversion performance through purposeful thermal and electrical control.
Accurate, affordable, and generalizable machine learning simulations of transition metal x-ray absorption spectra using the XANESNET deep neural network
Authors: Rankine C. D. , Penfold T. J.
Published: March 2022

The affordable, accurate, and generalizable prediction of spectroscopic observables plays a key role in the analysis of increasingly complex experiments. In this article, we develop and deploy a deep neural network—XANESNET—for predicting the lineshape of first-row transition metal K-edge x-ray absorption near-edge structure (XANES) spectra. XANESNET predicts the spectral intensities using only information about the local coordination geometry of the transition metal complexes encoded in a feature vector of weighted atom-centered symmetry functions. We address in detail the calibration of the feature vector for the particularities of the problem at hand, and we explore the individual feature importance to reveal the physical insight that XANESNET obtains at the Fe K-edge. XANESNET relies on only a few judiciously selected features—radial information on the first and second coordination shells suffices along with angular information sufficient to separate satisfactorily key coordination geometries. The feature importance is found to reflect the XANES spectral window under consideration and is consistent with the expected underlying physics. We subsequently apply XANESNET at nine first-row transition metal (Ti–Zn) K-edges. It can be optimized in as little as a minute, predicts instantaneously, and provides K-edge XANES spectra with an average accuracy of ∼±2%–4% in which the positions of prominent peaks are matched with a >90% hit rate to sub-eV (∼0.8 eV) error.
Spectroscopic characterization of singlet–triplet doorway states of aluminum monofluoride
Authors: Walter N. , Seifert J. , Truppe S. , Schewe H. C. , Sartakov B. G. , Meijer G.
Published: March 2022

Aluminum monofluoride (AlF) possesses highly favorable properties for laser cooling, both via the A1Π and a3Π states. Determining efficient pathways between the singlet and the triplet manifold of electronic states will be advantageous for future experiments at ultralow temperatures. The lowest rotational levels of the A1Π, v = 6 and b3Σ+, v = 5 states of AlF are nearly iso-energetic and interact via spin–orbit coupling. These levels thus have a strongly mixed spin-character and provide a singlet–triplet doorway. We here present a hyperfine resolved spectroscopic study of the A1Π, v = 6//b3Σ+, v = 5 perturbed system in a jet-cooled, pulsed molecular beam. From a fit to the observed energies of the hyperfine levels, the fine and hyperfine structure parameters of the coupled states and their relative energies as well as the spin–orbit interaction parameter are determined. The standard deviation of the fit is about 15 MHz. We experimentally determine the radiative lifetimes of selected hyperfine levels by time-delayed ionization, Lamb dip spectroscopy, and accurate measurements of the transition lineshapes. The measured lifetimes range between 2 and 200 ns, determined by the degree of singlet–triplet mixing for each level.
State-selective exciton–plasmon interplay in a hybrid WSe2/CuFeS2 nanosystem
Authors: Cheng Zhiqiang , Niu Xiaoyou , Jiang Shenlong , Zhang Qun
Published: March 2022

The integration of confined exciton and localized surface plasmon in a hybrid nanostructure has recently stimulated extensive interests. The mechanistic insights into the elusive exciton–plasmon interplay at the nanoscale are of both fundamental and applicable values. Herein, by taking a hybrid WSe2/CuFeS2 system as a prototype, in which the excitonic semiconductor WSe2 nanosheets are interfaced with the plasmonic semiconductor CuFeS2 nanocrystals to form a heterostructure, we design and perform an ultrafast dynamics study to glean information in this regard. Specifically, the band-alignment relationship between the two components enables the contrasting case studies in which the excitonic excited states of WSe2 are pre-selected to be on-/off-resonant with the plasmon band of CuFeS2. As revealed by the joint observations from steady-state absorption and photoexcitation-dependent/temperature-dependent femtosecond time-resolved transient absorption (fs-TA) spectroscopy, an effective energy transfer process occurs in this exciton–plasmon system where the energy donor (acceptor) is the excitonic WSe2 (plasmonic CuFeS2) and its efficiency is modulated by the exciton–plasmon coupling strength. Furthermore, as inferred from the temperature-dependent fs-TA analysis, the opening of such an energy-transfer channel turns out to take place during the early phase of plasmon decay (∼1 ps). In addition, the activation energy of energy transfer for a specific exciton-state-selected case is estimated (∼200 meV). This work provides a dynamics perspective to the plasmon semiconductor-involved exciton–plasmon interplay that features excited-state selectivity of exciton band and, hence, would be of guiding value for rational design and optimization of relevant applications based on exciton–plasmon manipulation.
Electrical switching of antiferromagnetic CoO | Pt across the Néel temperature
Authors: Grzybowski M. J. , Schippers C. F. , Bal M. E. , Rubi K. , Zeitler U. , Foltyn M. , Koopmans B. , Swagten H. J. M.
Published: March 2022

One of the most important challenges in antiferromagnetic spintronics is the readout of the Néel vector state. High current densities up to 108 Acm−2 used in the electrical switching experiments cause notorious difficulty in distinguishing between magnetic and thermal origins of the electrical signals. To overcome this problem, we present a temperature dependence study of the transverse resistance changes in the switching experiment with CoO | Pt devices. We demonstrate the possibility to extract a pattern of spin Hall magnetoresistance for current pulses with a density of 5×107A cm−2 that is present only below the Néel temperature and does not follow a trend expected for thermal effects. This is the compelling evidence for the magnetic origin of the signal, which is observed using purely electrical techniques. We confirm these findings by complementary experiments in an external magnetic field. Such an approach can allow determining the optimal conditions for switching antiferromagnets and be very valuable when no imaging techniques can be applied to verify the origin of the electrical signal.
Magnetostriction in microwave synthesized La0.5Ba0.5CoO3
Authors: Manikandan M. , Ghosh A. , Mahendiran R.
Published: March 2022

A single phase polycrystalline La0.5Ba0.5CoO3-d sample possessing cubic structure (space group Pm3̄m) was synthesized by microwave irradiation within 20 minutes of processing time and its structural, magnetic, electrical, and magnetostrictive properties were investigated. While the temperature dependence of field-cooled magnetization (M) in a field of H = 0.5 kOe indicates the onset of ferromagnetic transition at TC = 177 K, irreversibility between the zero field-cooled and field cooled M(T) persists even at H = 3 kOe. M(H) at 10 K does not saturate at the maximum available field and has a much smaller value (0.83 μB/Co in a field of 50 kOe) than 1.9 μB/Co expected for spin only contribution from intermediate Co3+ and Co4+ spins. Resistivity shows insulating behavior down to 10 K and only a small magnetoresistance (∼ -2% for H = 70 kOe) occurs around TC. All these results suggest a magnetically heterogeneous ground state with weakly interacting ferromagnetic clusters coexisting with a non-ferromagnetic phase. The length of the sample expands in the direction of the applied magnetic field (positive magnetostriction) and does not show saturation even at 50 kOe. The magnetostriction has a maximum value (λpar = 265 x 10-6) at 10 K and it decreases with increasing temperature. The smaller value of λpar compared to the available data on La0.5Sr0.5CoO3 (λpar = 900 x 10-6) suggests that the non-ferromagnetic matrix is most likely antiferromagnetic and it restrains the field-induced expansion of ferromagnetic clusters in the microwave synthesized La0.5Ba0.5CoO3-d sample.
Dualisms in Jihad
Authors: Patterson Katie J.
Published: March 2022

This paper explores how metaphors are employed in jihadist magazines to promote a dichotomist worldview of ‘us’
versus ‘them’, ‘good’ versus ‘bad’, ‘east’ versus ‘west’ and ‘right’ versus ‘wrong’. It argues that juxtapositions in both
language and thought help writers to reaffirm and/or challenge certain paradigms. The approach uses critical metaphor analysis
(Charteris-Black 2004) to investigate qualitative evidence of conceptual metaphors,
focusing on the domains life is a seed, conflict is a relationship between predator and prey, and faith is light/lack
of faith is darkness. Dichotomous language in these domains (e.g., ‘seed’ versus ‘weed’; ‘sheep’ versus ‘wolves’; the
‘spark of Jihad’ versus the ‘shadow’ of Western governments) helps to position extremist groups on the right side of a number of
paradigms. The use of binary metaphors also permits simultaneously conflicting conceptualisations; for instance, jihadists are
both innocent victims and merciless defenders of their faith, depending on with whom or what they are juxtaposed. The research
concludes that the use of binary metaphors serves to underscore entrenched paradigms of ‘good’ versus ‘bad’, thus allowing the
writers to frame their discourse in a way that justifies and promotes their extremist agenda.
Burmese pythons exhibit a transient adaptation to nutrient overload that prevents liver damage
Authors: Magida Jason A. , Tan Yuxiao , Wall Christopher E. , Harrison Brooke C. , Marr Thomas G. , Peter Angela K. , Riquelme Cecilia A. , Leinwand Leslie A.
Published: March 2022

As an opportunistic predator, the Burmese python (Python molurus bivittatus) consumes large and infrequent meals, fasting for up to a year. Upon consuming a large meal, the Burmese python exhibits extreme metabolic responses. To define the pathways that regulate these postprandial metabolic responses, we performed a comprehensive profile of plasma metabolites throughout the digestive process. Following ingestion of a meal equivalent to 25% of its body mass, plasma lipoproteins and metabolites, such as chylomicra and bile acids, reach levels observed only in mammalian models of extreme dyslipidemia. Here, we provide evidence for an adaptive response to postprandial nutrient overload by the python liver, a critical site of metabolic homeostasis. The python liver undergoes a substantial increase in mass through proliferative processes, exhibits hepatic steatosis, hyperlipidemia-induced insulin resistance indicated by PEPCK activation and pAKT deactivation, and de novo fatty acid synthesis via FASN activation. This postprandial state is completely reversible. We posit that Burmese pythons evade the permanent hepatic damage associated with these metabolic states in mammals using evolved protective measures to inactivate these pathways. These include a transient activation of hepatic nuclear receptors induced by fatty acids and bile acids, including PPAR and FXR, respectively. The stress-induced p38 MAPK pathway is also transiently activated during the early stages of digestion. Taken together, these data identify a reversible metabolic response to hyperlipidemia by the python liver, only achieved in mammals by pharmacologic intervention. The factors involved in these processes may be relevant to or leveraged for remediating human hepatic pathology.
Electron drag force in EUV induced pulsed hydrogen plasmas
Authors: Chaudhuri M , Yakunin A , van de Kerkhof M , Snijdewind R
Published: March 2022

Extreme ultraviolet (EUV) induced pulsed plasma is unique due to its transient characteristics: the plasma switches between non-thermal state (when EUV power is ON at the beginning of the pulse) and thermal state (end of the pulse at ∼20 μs). It is shown that although electron drag force acting on nm size particles in hydrogen plasma is negligible compared to the ion drag force at the beginning of the pulse, however it can be dominant at the end of the pulse and can play important role in particle transport leading to defectivity issues for semiconductor chip production technologies.
Improved training in paraffin-wax impregnated Nb3Sn Rutherford cables demonstrated in BOX samples
Authors: Daly Michael , Auchmann Bernhard , Brem André , Hug Christoph , Sidorov Serguei , Otten Simon , Dhallé Marc , Guo Zichuan , Kario Anna , Ten Kate Herman
Published: March 2022

Resin-impregnated high-field Nb3Sn type of accelerator magnets are known to require extensive training campaigns and even may exhibit performance-limiting defects after thermal or electromagnetic cycling. In order to efficiently explore technological solutions for this behaviour and assess a wide variety of impregnation material combinations and surface treatments, the BOnding eXperiment (BOX) sample was developed. BOX provides a short-sample test platform featuring magnet-relevant Lorentz forces and exhibits associated training. Here we report on the comparative behaviour of BOX samples comprising the same Nb3Sn Rutherford cable but impregnated either with common resins used in high-field magnets, or with less conventional paraffin wax. Remarkably, the two paraffin wax-impregnated BOX samples reached their critical current without training and are also resilient to thermal and mechanical cycling. These rather encouraging results strongly contrast to those obtained with resin impregnated samples, which show the characteristic extensive training and at best barely reach their critical current value.
Low-cost Access to the Deep, High-cadence Sky: the Argus Optical Array
Authors: Law Nicholas M. , Corbett Hank , Galliher Nathan W. , Gonzalez Ramses , Vasquez Alan , Walters Glenn , Machia Lawrence , Ratzloff Jeff , Ackley Kendall , Bizon Chris , Clemens Christopher , Cox Steven , Eikenberry Steven , Howard Ward S. , Glazier Amy , Mann Andrew W. , Quimby Robert , Reichart Daniel , Trilling David
Published: March 2022

New mass-produced, wide-field, small-aperture telescopes have the potential to revolutionize ground-based astronomy by greatly reducing the cost of collecting area. In this paper, we introduce a new class of large telescope based on these advances: an all-sky, arcsecond-resolution, 1000 telescope array which builds a simultaneously high-cadence and deep survey by observing the entire sky all night. As a concrete example, we describe the Argus Array, a 5 m-class telescope with an all-sky field of view and the ability to reach extremely high cadences using low-noise CMOS detectors. Each 55 GPix Argus exposure covers 20% of the entire sky to m

g
= 19.6 each minute and m

g
= 21.9 each hour; a high-speed mode will allow sub-second survey cadences for short times. Deep coadds will reach m

g
= 23.6 every five nights over 47% of the sky; a larger-aperture array telescope, with an étendue close to the Rubin Observatory, could reach m

g
= 24.3 in five nights. These arrays can build two-color, million-epoch movies of the sky, enabling sensitive and rapid searches for high-speed transients, fast-radio-burst counterparts, gravitational-wave counterparts, exoplanet microlensing events, occultations by distant solar system bodies, and myriad other phenomena. An array of O(1000) telescopes, however, would be one of the most complex astronomical instruments yet built. Standard arrays with hundreds of tracking mounts entail thousands of moving parts and exposed optics, and maintenance costs would rapidly outpace the mass-produced-hardware cost savings compared to a monolithic large telescope. We discuss how to greatly reduce operations costs by placing all optics in thermally controlled, sealed domes with only a few moving parts. Coupled with careful software scope control and use of existing pipelines, we show that the Argus Array could become the deepest and fastest Northern sky survey, with total costs in the $20M range.