bluuebunny/crossref_metadata_2025 huggingface dataset:
20.2.1.8.15 Synthesis of Carboxylic Acids with Retention of the Functional Group (Update 2024)
Authors: Sawamura M. , Shimizu Y.
Published: March 2024

Carboxylic acids are readily available feedstock materials, and are also found in natural products, pharmaceuticals, agrochemicals, and other biologically active compounds. Hence, efficient methods to transform carboxylic acids into other value-added compounds is of great importance. This review is an update to Science of Synthesis Section 20.2.1.8 on the synthesis of carboxylic acids with “retention of the functional group”. The main focus of this review is placed on asymmetric reactions and catalytic reactions, along with practical stoichiometric reactions, reported in the period 2010–2022. The transformations discussed include α-functionalizations, conjugate additions, and C(sp2)—H as well as C(sp3)—H functionalizations.
Which investors support the transition toward a low-carbon economy? Exit and Voice in mutual funds
Authors: Zink Jonas
Published: March 2024

Reducing portfolio carbon footprints (Exit) and voting in favor of climate-related shareholder proposals (Voice) are among the main actions that investors can take to promote an accelerated transition toward a low-carbon economy. This paper studies three important investor groups that can be instrumental in driving the transition and evaluates their Exit and Voice behavior. I find that the five largest asset managers perform poorly on Exit and Voice over the full sample period but improved on both in more recent years. Only a small fraction of signatories to sustainable investor initiatives are supportive of the transition. Counterintuitively, investors who perform poorly on Exit, perform well on Voice. Finally, I examine the financial consequences of employing Exit and Voice and find that Exit is positively related to risk-adjusted fund returns; however, this is not necessarily attributable to superior skill of fund managers.
Central Bank Digital Currencies and financial integrity: finding a new trade-off between privacy and traceability within a changing financial architecture
Authors: Soana Giulio , de Arruda Thomaz
Published: March 2024

In an increasingly digitised world, and within the new reality of digital finance, a fully digitised public currency seems to be a natural step. To this end, central banks have been testing the possibility to issue a digital form of the traditional fiat currency (so-called Central Bank Digital Currency-CBDC). As these projects steadily progress, and in some cases, reach the implementation phase, a myriad of questions, from legal to macroeconomic, arise. This paper aims to focus, in particular, on two complementary and co-related aspects involving CBCDs: (i) how can the full digitalisation and centralisation of the transaction ledger be combined with privacy and (ii) to what extent CBDCs affect the allocation of burden and the responsibility over supervision of retail transactions. Eminently, the use of cash ensures a form of default privacy that protects the individual against State and private intrusion. While this privacy has caused concern, due to its criminogenic potential, and has been consequently limited by anti-money laundering (AML) regulations, the remaining cone of shadow cash guarantees is a crucial limit to control. In the context of a shifting financial system, undergoing deep transformation due to increasing datafication and decentralisation of the market, a new governance of financial supervision and record-keeping—up to now based on a unique and centralised ledger—is crucial to redefine the trade-off between financial integrity and privacy. This article will examine the origins and characteristics of CBDCs, to then analyse how the trade-off between control and privacy is set to reshape this new architecture.
The determinants of mental well-being of healthcare professionals during the COVID-19 pandemic
Authors: Ceular-Villamandos Nuria , Navajas-Romero Virginia , del Rio Lorena Caridad y Lopez , Vazquez-Garcia Maria Jesus
Published: March 2024

In this study, the objective is to understand the causal factors that influence the mental well-being of healthcare workers during the COVID-19 pandemic, using Karasek’s Job Demand Control Social Model (JDCS) as the research framework. For this purpose the database Eurofound’s Living Working and COVID-19 survey is used; it was carried out using sampling design techniques in all 27 countries of the European Union. A sample of 4626 employees in the health sector is used, and structural equation models are specified to analyze causality. The analysis revealed significant associations between several factors: physical and mental work demands (p < 0.001), availability of personal protective equipment (p = 0.035), support from supervisors (p < 0.001), support from peers (p < 0.001), and age (p < 0.007). These findings, offering valuable insights into understanding and improving the management of health institutions, can serve as a foundation for developing strategies to support and enhance the mental health of healthcare professionals. Ultimately, this benefits both the workforce and the quality of healthcare services provided, particularly in preparing for potential future crises.
Quantum model in the context of six-level atom and deformed Lie algebra: Entanglement and statistical properties
Authors: Abdel-Khalek S. , Algarni M. , Berrada K.
Published: March 2024

In this work, we study the interplay between an atomic system with six levels configured in a cascade-type and one-mode fields in the framework of the f-coherent states. We explore the considered system dynamic properties under the effects of field nonlinearity and the number of photon transitions. In particular, we consider the quantum coherence, atomic upper level-occupation probability, and atom–field entanglement of a system when the effect of deformation is considered. Moreover, we analyze the dynamic of the Mandel parameter as a quantifier of the statistical properties of the field in the presence of deformation when the field is initially in coherent states.
Ion diffusion captures composition-dependent anomalies in water–DMSO binary mixtures
Authors: Mondal Sangita , Bagchi Biman
Published: March 2024

Aqueous dimethyl sulfoxide (Aq-DMSO) binary mixture exhibits many fascinating composition-dependent anomalies that are explained by using the peculiarities of the water–DMSO hydrogen bond. Ions can couple strongly to these composition-dependent anomalies to produce exotic dynamics of their own. We carry out theoretical studies using computer simulations to understand the structural and dynamical aspects of rigid monovalent cations (Li+, Na+, K+, Rb+, and Cs+) in aqueous DMSO solutions, with chloride as the counterion. We uncover a number of composition-dependent ion diffusion anomalies, which can be traced back to the interplay between the size-dependent charge density of the ion and the resulting difference in interactions of the ion with water and DMSO molecules. Size and composition dependence of the diffusion coefficients of the five ions exhibit fascinating variations that can be explained partially.
Graphene quantum dot bolometer for on-chip detection of organic radical
Authors: Hrubý J. , Laguta O. , Sojka A. , Marie L. St. , Myers-Ward R. , Gaskill D. K. , El Fatimy A. , Barbara P. , Neugebauer P.
Published: March 2024

We present a proof-of-concept magnetic resonance detection of organic radical 2,2-diphenyl-1-picrylhydrazyl via a nanostructured on-chip graphene quantum dot bolometer. In a common electron paramagnetic resonance setup, the microwave propagates from a source into a sample and back to a detector. Yet, by using on-chip detection, it is possible to skip the whole detection arm and, thus, mitigate lab expenses on instrument and cooling costs. The bolometric detection was demonstrated at a frequency of 151 GHz and a temperature of 15 K.
Enhanced terahertz emission in a large-area photoconductive antenna through an array of tightly packed sapphire fibers
Authors: Zenchenko N. V. , Lavrukhin D. V. , Galiev R. R. , Yachmenev A. E. , Khabibullin R. A. , Goncharov Yu. G. , Dolganova I. N. , Kurlov V. N. , Otsuji T. , Zaytsev K. I. , Ponomarev D. S.
Published: March 2024

Experimental observation of the enhanced terahertz (THz) emission in a large-area photoconductive antenna-emitter (LAE), boosted by an array of cylindrical sapphire-fiber-based microlenses, is reported. The observed enhancement is achieved, thanks to the sharp focusing of a pump laser beam near the semiconductor surface, for which the high-refractive-index sapphire lenses are used. We predict numerically and confirm experimentally a considerable enhancement in the emitted THz spectral power for such a sapphire-fiber-coupled LAE, as compared to an ordinary one with an equal electrode topology. In fact, a ≃8.5-fold THz power boost is achieved, resulting in a +9.3 dB increase in the dynamic range. The results of our findings can be used to improve the performance of large-area THz devices, aimed at meeting the demands of rapidly developed THz spectroscopy, imaging, sensing, and exposure technologies.
An interface tracking, finite volume code for modeling axisymmetric implosion of a rotating liquid metal liner with free surface
Authors: Khalzov Ivan V. , Krotez Daymon , Ségas Raphaël
Published: March 2024

We present Integrated System Model-hydrodynamics (ISM-hydro)—an interface tracking, finite volume code for modeling a shaped implosion of a rotating, initially cylindrical, fluid shell (liner) with a free surface. The code is a novel implementation of the mixed Lagrangian–Eulerian approach, applied to a compressible fluid in an axisymmetric geometry described by cylindrical coordinates (r, ϕ, z). In ISM-hydro, a structured quadrilateral mesh follows fluid elements in the r-direction (radially Lagrangian) and is fixed in the z-direction (axially Eulerian). This approach accurately captures the motion of the liner's free surface, making it an interface tracking method. Using this mesh, we derive a finite volume discretization of the axisymmetric Euler equations for a rotating compressible fluid that has an exact balance of kinetic energy. An extensive comparison between ISM-hydro and the open-source software OpenFOAM is presented; results for different test cases show very good agreement in simulated implosion trajectories and flow fields. ISM-hydro is the purely hydrodynamic component of the Integrated System Model (ISM), a framework developed at General Fusion (GF) for comprehensive predictive modeling of GF's magnetized target fusion (MTF) scheme, where an imploding rotating liquid metal liner compresses a magnetized plasma target to fusion conditions. Among advantages of the code is its speed: a full implosion simulation with a coarse mesh takes on the order of one minute on a single core while preserving high accuracy. This makes ISM-hydro a valuable tool for the design optimization of GF's MTF machines.
Terahertz metallic waveguide with meta-holes for bidirectional conversion between two-dimensional guided waves and free-space waves
Authors: Peng Tao , Zhang Lei , Wang Ning , Chen Wei , Zhang Min , Su Hong , Li Ling , Liang Huawei
Published: March 2024

The conversion between guided and free-space waves is crucial for achieving integrated terahertz (THz) communication and signal processing. Herein, a bidirectional conversion mechanism is proposed for bridging two-dimensional (2D) guided waves and free-space waves, which is demonstrated by the wave manipulation of a metallic waveguide with meta-holes (MWMH). Compared with the conventional conversion between one-dimensional guided waves and free-space waves, in the proposed bidirectional conversion process, meta-holes can arbitrarily manipulate the phase of THz waves in higher dimensions, which enables stronger beam-manipulation capability and a higher gain. When used as a transmitting antenna, the MWMH exhibits excellent performance, i.e., a high gain (33.3 dBi), a high radiation efficiency (∼90%), and flexible beam manipulation. When the MWMH is reversely employed as a receiving antenna to obtain the focus of 2D guided waves, it achieves a gain of 27 dB and a focusing efficiency of 50.4%. The measured results for both the transmitting and receiving antennas agree well with the simulation results. The proposed bidirectional conversion mechanism facilitates the development of THz integrated photonic devices and is promising for application in the sixth-generation mobile communication, radar detection, and nondestructive testing.
Persistent spin texture in ferroelectric Hf0.5Zr0.5O2
Authors: Li Huinan , Chen Xu , Zhang Qin , Dou Mingbo , Yu Yue , Zhuravlev M. Ye. , Nikolaev A. V. , Wang Xianjie , Tao L. L.
Published: March 2024

Persistent spin texture (PST) refers to the unidirectional spin configuration in momentum space and preserves the SU(2) spin rotation symmetry, which protects the spin coherence against the relaxation and renders an ultimately infinite spin lifetime. In this regard, it would be desirable to find high-quality quantum materials sustaining the intrinsic PST. Here, based on density-functional theory calculations, we show that the ferroelectric Hf0.5Zr0.5O2 sustains a PST over large area of Brillouin zone around the conduction band minimum, while the Rashba-type spin texture dominates around the valence band maximum. Based on the group-theoretical analysis, we construct an effective k·p Hamiltonian model and demonstrate that the PST arises from the significant anisotropy of spin splitting, which pins the spin–orbit field to certain direction. In addition, we elucidate the spin SU(2) symmetry for the discovered PST. Given the fact that Hf0.5Zr0.5O2 is compatible with silicon semiconductor technologies, our work discovers a high-quality oxide material sustaining the PST, which holds great promise for spin-orbitronic applications.
Adaptive thermodynamic consistency control via interface thickness in pseudopotential lattice Boltzmann method across wide temperature ranges
Authors: Dai Zheng , Zhu Junhao , Wang Zhongyi , Chu Shuguang , Wang Yanhua
Published: March 2024

Multiphase flow phenomena are ubiquitous in real-life applications, and the pseudopotential-based lattice Boltzmann multiphase simulation method has gained extensive usage in fields such as fuel cells, energy storage materials, and boiling heat transfer. Over the past two decades, significant improvements have been made to the pseudopotential model. These advancements have greatly enhanced its accuracy in simulating various processes. In this paper, we employ a numerical stability-based unit conversion scheme to ensure an accurate representation of real-world material properties. Additionally, we introduce a more precise non-ideal two-parameter gas state equation Modified Peng-Robinson (MPR) that closely aligns with experimental data, surpassing the commonly used single-parameter Peng-Robinson state equations. Furthermore, we compare the accuracy of the two-state equations for polar and non-polar substances, finding improved accuracy for non-polar substances and a higher degree of fidelity for polar substances when using the MPR equation. We analyze the constant correction coefficients chosen for thermodynamic consistency regulation from the perspectives of vapor-liquid interface thickness and numerical stability, both when held constant and when employing a dynamic correction approach that balances vapor-liquid interface width, numerical stability, and thermodynamic consistency. Finally, we validate to ensure its practical applicability.
Experimental determination of the band offsets at the UWBG p-LiGa5O8/Ga2O3 interface
Authors: Zhang Kaitian , Thirupakuzi Vangipuram Vijay Gopal , Chae Christopher , Hwang Jinwoo , Zhao Hongping
Published: March 2024

LiGa5O8, a recently discovered ultrawide bandgap semiconductor exhibiting p-type conductivity at room temperature, is grown on (010) β-Ga2O3 substrate. Utilizing a mist chemical vapor deposition method, LiGa5O8 thin film grown on insulating Ga2O3 substrate exhibits hole concentration ∼2.31 × 1018 cm−3 and hole mobility ∼2.07 cm2/V s. The resulting heterostructure is characterized comprehensively. A smooth, uniform film growth was observed by scanning electron microscopy and atomic force microscopy imaging. Cross-sectional scanning transmission electron microscopy and x-ray diffraction confirm the growth of spinel cubic crystal structure of LiGa5O8 along the [110] direction. Moreover, the valence and conduction band offsets at p-LiGa5O8/β-Ga2O3 heterointerface were determined via x-ray photoelectron spectroscopy. The determined band alignments at LiGa5O8/β-Ga2O3 interface reveal the formation of a type-II (staggered) heterojunction. The experimental measurements provide valuable parameters of the band offsets at the heterointerface, addressing a crucial aspect for future power electronic device design and fabrication based on β-Ga2O3 ultrawide bandgap semiconductors.
Synergistic effect of electrical bias and proton irradiation on the electrical performance of β-Ga2O3 p–n diode
Authors: Yue Shaozhong , Wang Yingzhe , Zheng Xuefeng , Pan Ailing , Hong Yuehua , Wang Xiaohu , Gong Sunyan , Zhu Tian , Zhang Fang , Ma Xiaohua , Hao Yue
Published: March 2024

The synergistic impact of reverse bias stress and 3 MeV proton irradiation on the β-Ga2O3 p–n diode has been studied from the perspective of the defect in this work. The forward current density (JF) is significantly decreased with the increase in proton irradiation fluence. According to the deep-level transient spectroscopy results, the increase in the acceptor-like trap with an energy level of EC-0.75 eV within the β-Ga2O3 drift layer, which is most likely to be Ga vacancy-related defects, can be the key origin of the device degradation. The increase in these acceptor-like traps results in the carrier concentration reduction, which in turn leads to a decrease in JF. Furthermore, compared with the case of proton irradiation with no bias, the introduction of −100 V electrical stress induced a nearly double decrease in JF. Based on the capacitance–voltage (C–V) measurement, with the support of the electric field, the carrier removal rate increased from 335 to 600 cm−1. Similar to the above-mentioned phenomenon, the trap concentration also increased significantly. We propose a hypothesis elucidating the synergistic effect of electrical stress and proton irradiation through the behavior of recoil nuclei under the electric field.
Radiological safety assessment for transportation of reactor pressure vessel during decommissioning of a nuclear power plant in Korea
Authors: Kwak Minwoo , Kim Hyeok Jae , Oh Ga-Eun , Shin Sang Won , Kim Kwang Pyo
Published: March 2024

In Korea, decommissioning of nuclear power plants and transportation of the decommissioning waste are expected to expand in the near future. It is necessary to confirm that radiological risks to the public and workers are not significant through radiological safety assessment. The objective of this study is to assess the radiological safety for transportation of RPV waste, which is a major decommissioning waste with relatively high level of radioactivity. It was assumed that the waste would be transported to the Gyeongju disposal facility by land transportation. First, the source term and transportation method of the RPV waste were determined, and the external dose rates from the waste were calculated using MCNP. Then, transportation scenarios were assumed under both normal and accident conditions. Under the scenarios, radiation doses were calculated using the RADTRAN. Under normal operation scenarios without a transportation accident, assuming 40 shipments per year, the average individual doses for the public ranged from 6.56

×

10−6 to 2.18

×

10−2 mSv yr−1. The maximum individual doses for only a single shipment ranged from 2.43

×

10−6 to 3.14

×

10−1 mSv. For cargo handlers and vehicle crew members, the average doses were 2.26

×

101 mSv yr−1 and 2.95 mSv yr−1, respectively. Under transportation accident scenarios, average individual radiological risks which are product of the radiation doses and the annual accident rates ranged from 1.14

×

10−11 to 1.61

×

10−10 mSv yr−1 by transportation route segment when considering the transportation accident rate. Average individual doses assuming transportation accident occurrence ranged from 2.62

×

10−4 to 1.42

×

10−3 mSv. The maximum individual dose under accident conditions was 7.99

×

10−2 mSv. The calculated doses were below the regulatory limits in Korea. However, relatively high doses were observed for cargo handlers and vehicle crew members because of conservative assumptions. This study results can be used as basic data for the radiological safety assessment for the decommissioning waste transportation in the future.
PPP-AR reference satellite selection based on the observation quality factors
Authors: Li Mengyuan , Huang Guanwen , Wang Le , Xie Wei
Published: March 2024

Precise point positioning ambiguity resolution (PPP-AR) can effectively improve positioning accuracy and convergence time. In PPP-AR, the double-difference ambiguity between satellite pairs must be fixed. Therefore, it requires the selection of one satellite as a reference to conduct single-difference observations. Usually, the satellite with the highest elevation is selected as the reference satellite, however, once this satellite has a cycle slip or signal interference, its ambiguity will be reinitialized, resulting in the calculated wide-lane and narrow-lane ambiguities are not accurate enough, which further affects all the ambiguities fixed rates and positioning accuracies. In this contribution, we propose a multi-indicators comprehensive evaluation method of the global navigation satellite system (GNSS) based on entropy weight-grey correlation analysis for reference satellite selection of PPP-AR. The comprehensive evaluation includes the observations index selection, the index normalization, the calculation of index entropy weight and the grey correlation analysis. According to the new method, the quality ranking of satellite observations for each epoch can be obtained, and the observation value with the highest ranking is used as the reference satellite during the PPP-AR. One-week observations from 243 multi-GNSS experiment stations are selected to conduct GPS-only, Galileo-only and BDS-3-only kinematic PPP-AR, and the reference satellite selection method using the highest-elevation and the proposed method is applied, respectively. The results show that the PPP performance for the new method can be improved in the positioning accuracies, convergence time and ambiguity fixed rates. The positioning accuracies of three-dimensional directions can be improved by about 5.54%, 8.81% and 6.02% for GPS, BDS-3 and Galileo, respectively. The average improvements of convergence time in the east, north and up directions are 4.67%, 2% and 4% for GPS, BDS-3 and Galileo, respectively. The ambiguity fixed rates are improved by 7.31%, 6.89% and 1.45% for GPS, BDS-3 and Galileo between the 80%-100% range, respectively.
Robust residual-guided iterative reconstruction for sparse-view CT in small animal imaging
Authors: Zhang Jianru , Wang Zhe , Cao Tuoyu , Cao Guohua , Ren Wuwei , Jiang Jiahua
Published: March 2024

Objective. We introduce a robust image reconstruction algorithm named residual-guided Golub–Kahan iterative reconstruction technique (RGIRT) designed for sparse-view computed tomography (CT), which aims at high-fidelity image reconstruction from a limited number of projection views. Approach. RGIRT utilizes an inner-outer dual iteration framework, with a flexible least square QR (FLSQR) algorithm implemented in the inner iteration and a restarted iterative scheme applied in the outer iteration. The inner FLSQR employs a flexible Golub–Kahan bidiagonalization method to reduce the size of the inverse problem, and a weighted generalized cross-validation method to adaptively estimate the regularization hyper-parameter. The inner iteration efficiently yields the intermediate reconstruction result, while the outer iteration minimizes the residual and refines the solution by using the result obtained from the inner iteration. Main results. The reconstruction performance of RGIRT is evaluated and compared to other reference methods (FBPConvNet, SART-TV, and FLSQR) using projection data from both numerical phantoms and real experimental Micro-CT data. The experimental findings, from testing various numbers of projection views and different noise levels, underscore the robustness of RGIRT. Meanwhile, theoretical analysis confirms the convergence of residual for our approach. Significance. We propose a robust iterative reconstruction algorithm for x-ray CT scans with sparse views, thereby shortening scanning time and mitigating excessive ionizing radiation exposure to small animals.
Stochastic synchronization of Kuramoto-oscillator network with pinning control
Authors: Zhu Jian , Li Shihan , Sun Yongzheng , Shi Hongjun , Ma Caoyuan
Published: March 2024

The issue of time cost for the Kuramoto-oscillator network synchronization has received widespread attention. However, there is no relevant research on the stochastic synchronization of the Kuramoto-oscillator network with partial uncontrollable oscillators. This article investigates the synchronization problem of the Kuramoto-oscillator network in noisy environments using the pinning control strategy and multilayer distributed control. Previous research requires control of all oscillators, which implies a great control cost. To reduce the control cost, the finite/fixed time pinning controllers are designed to provide the conditions for synchronization in noisy environments, and then the upper bounds on the convergence time of the network are estimated. Finally, numerical simulations are performed to justify the theoretical conclusions.
Advanced medical image encryption techniques using the fractional-order Halvorsen circulant systems: dynamics, control, synchronization and security applications
Authors: Yousfi Hasna , Islam Yousuf , He Shaobo , Gasri Ahlem , Mehedi Hassan MD
Published: March 2024

In this paper, we describe the Halvorsen circulant system (HCS) with a fractional-order Caputo derivative and its qualitative properties. The numerical solution of the fractional order Halvorsen circulant system (FO-HCS) is proposed based on the Adomian decomposition method (ADM). The ADM method is used to solve fractional-order systems. Then, dynamics is analyzed using different methods including Lyapunov exponents, bifurcation diagrams, complexity, and phase diagrams. This paper also investigates the stabilization and synchronization of identical FO-HCS, and stability theory proves adaptive feedback control and synchronization. In addition, using the fractional-order system’s remarkable properties to develop the image encryption technique using the extended fractional sequences. The proposed method uses a keystream generator for high security based on the enhanced fractional Halvorsen circulant chaotic behavior. The simulation results confirm that it can resist various attacks, including statistical analysis, differential attacks, brute-force attacks, known plaintext attacks, and chosen plaintext attacks, with high security, and low computational complexity. Finally, the results of the simulation and its performance prove that it's effective and secure in image data.
Persistency of quantum non-multi-local correlations in noisy acyclic networks
Authors: Yang Shuyuan , Hou Jinchuan , He Kan
Published: March 2024

The topic of network quantum nonlocal correlations arises from the large-scale quantum communications. It has been demonstrated that non-m-local correlations (m is the number of sources) in some special kinds of networks will decay under the influence of noises from imperfect devices as these networks extend, including linear and star networks. Furthermore, we observe that under the same noisy level, persistency of non-multi-local correlations in aforementioned different kinds of networks appears obvious discrepancy. Therefore, it becomes a natural and challenging task to check the persistency of non-multi-locality in more complex acyclic network, since star and linear networks can be regarded as acyclic networks. It is worth noting that an acyclic network is one indeterminate forked tree-shaped networks. So the study is focused on the tree-shaped network. We first devote to discussing the determinate forked case. We obtain inequality persistency criteria of determinate k-forked tree-shaped network non-(s

n
(k))-local correlations (s

n
(k) is the number of total sources). We show that the larger the fork number k is larger, the better the non-multi-locality of this network persists. In the indeterminate forked case, the inequality persistency criteria are also established. We observe that the larger the number of parties in the last layer of an acyclic network, the better the non-multi-locality of this network is persisted. This theoretical research may guide us how to build quantum networks with the stronger correlation in practical communications.
Resonant tunnelling of wave packet
Authors: Albaid Abdelhamid
Published: March 2024

This paper examines tunnelling through potential well protected by double barriers as well as the motion of a wave packet encountering this type of potential. Various options for the left and right barriers’ penetration factors are taken into consideration. When one of the penetration factors has limiting value of 0.5, the transmission coefficients turns out to be independent of incoming energy of the particle and the width of potential well. When both penetration factors have a limiting value of 0.5, a scenario similar to resonance tunneling is achieved. Furthermore, by doing the wave packet analysis, we found that the width and height of potential barriers have a negligible impact on the probability of finding the particle inside the potential well in the limit of large penetration factors.
Cauchy matrix approach to three non-isospectral nonlinear Schrödinger equations
Authors: Tefera Alemu Yilma , Li Shangshuai , Zhang Da-jun
Published: March 2024

This paper aims to develop a direct approach, namely, the Cauchy matrix approach, to non-isospectral integrable systems. In the Cauchy matrix approach, the Sylvester equation plays a central role, which defines a dressed Cauchy matrix to provide τ functions for the investigated equations. In this paper, using the Cauchy matrix approach, we derive three non-isospectral nonlinear Schrödinger equations and their explicit solutions. These equations are generically related to the time-dependent spectral parameter in the Zakharov–Shabat–Ablowitz–Kaup–Newell–Segur spectral problem. Their solutions are obtained from the solutions of unreduced non-isospectral nonlinear Schrödinger equations through complex reduction. These solutions are analyzed and illustrated to show the non-isospectral effects in dynamics of solitons.
Equilibrium reconstruction constrained by the consistency of current simulation on EAST
Authors: Qian Z.H. , Xiang N. , Huang Y.H. , Chen J.L. , Zhai X.M. , Ma L.H. , Wu X.M. , Li G. , Li G.Q. , Qian J.P. , Lin G.L. , Jin Y.F. , Zhao H.L. , Ye K.X. , Liu H.Q. , Lyu B. , Zang Q.
Published: March 2024

The attainment of a reliable equilibrium is a critical aspect of tokamak experiments and physics analysis. A common method for establishing a reliable equilibrium current involves reconstructing it from indirect measurements, such as those obtained from polarimeter-interferometers (POINT) and motional Stark effect (MSE) systems. However, uncertainties still exist in the reconstruction results. For the equilibrium reconstruction on the EAST tokamak, which is based on the POINT system, the primary sources of uncertainty are the limited scope of measurements and the sensitivity of the reconstruction process. This paper proposes an enhanced approach that utilizes current simulation as a constraint to maintain consistency between the initial equilibrium and the simulated results. The radio frequency waves driven current is identified as a particularly influential component due to its interaction with the q profiles of the equilibrium and the deposition region of the waves. Two specific discharges are presented to illustrate how a new equilibrium can be achieved, which enhances consistency between the equilibrium and the simulated current, taking into account the dependencies of various components.
Enhancing stance robustness and jump height in bipedal muscle-actuated systems: a bioinspired morphological development approach
Authors: Badie Nadine , Schmitt Syn
Published: March 2024

Recognizing humans’ unmatched robustness, adaptability, and learning abilities across anthropomorphic movements compared to robots, we find inspiration in the simultaneous development of both morphology and cognition observed in humans. We utilize optimal control principles to train a muscle-actuated human model for both balance and squat jump tasks in simulation. Morphological development is introduced through abrupt transitions from a 4 year-old to a 12 year-old morphology, ultimately shifting to an adult morphology. We create two versions of the 4 year-old and 12 year-old models— one emulating human ontogenetic development and another uniformly scaling segment lengths and related parameters. Our results show that both morphological development strategies outperform the non-development path, showcasing enhanced robustness to perturbations in the balance task and increased jump height in the squat jump task. Our findings challenge existing research as they reveal that starting with initial robot designs that do not inherently facilitate learning and incorporating abrupt changes in their morphology can still lead to improved results, provided these morphological adaptations draw inspiration from biological principles.
Modulation of the cold tongue mode (CTM) in tropical cyclone genesis over the western North Pacific during 1975–2021
Authors: Lin Chunqiao , Fan Lingli , Zhu Congwen , Xu Jianjun
Published: March 2024

The cold tongue mode (CTM) in the tropical Pacific enhanced with the global warming in the recent decades. Here, we show that the change of oceanic thermal condition and atmospheric circulation plays a critical role in the tropical cyclones (TCs) genesis in the western North Pacific (WNP). The frequency of TCs in the WNP decreases with its northwest movement, when the CTM transitions from its negative phase in 1975–1997(P1) to positive phase in 1998–2021 (P2). Intercomparison of the TC activities between P1 and P2, we found that the main reason responsible for decreasing of TC genesis is from reducing of meridional and zonal heat transportation. And the northwest movement of TC position is driven by the heat increasing at the western and northern boundary areas. In addition, the northwest movement of TC is dominated by the atmospheric circulation associated with local Walker circulation and Hadley cell.
Comment on ‘Anomalous diffusion originated by two Markovian hopping-trap mechanisms’
Authors: Shkilev V P
Published: March 2024

The authors of the paper (Vitali et al 2022 J. Phys. A: Math. Theor.
55 224012) analyzed a simple CTRW model with a waiting time distribution defined as the weighted sum of two exponential distributions. They showed that their model meets many paradigmatic features that belong to the anomalous diffusion as it is observed in living systems. This comment point out the previous paper that considers a similar model and improves on the authors’ result regarding the time dependence of the mean-square displacement.
Research on laser repair technology for surface defects of flywheel disc steel plate
Authors: Mao Yuhang , Shi Guangfeng , Guan Yanji , Lü Hongbing , Li Junye
Published: March 2024

Flywheel disc steel plate, used in the rear end of the engine disc-shaped parts, is one of the important components that make up the engine. However, during the manufacturing process, its surface is prone to defects such as scratches and dents. The defects position of the steel plate will produce the phenomenon of stress concentration, which directly leads to its scrapping. To solve this problem, a laser repair method is proposed, which uses laser with high energy density to repair surface defects. Firstly, the repairable defect depth under different laser parameters is predicted by finite element simulation. The temperature of the steel plates increases with the increase of the laser power density and decreases with the increase of the scanning speed. When the laser power density is

5.57
×

10

11

W m−2 and the scanning speed is 120 mm s−1, surface defects of various depths can be repaired, and the size of the melt pool is moderate. Then, process experiments were conducted, and the results showed that good repair effects can be achieved when the laser power is 14 W, the repetition frequency is 130 kHz, the scanning speed is 120 mm s−1, and the scanning spacing is 0.02 mm. Finally, the surface with original surface roughness of 2.370 μm can be repaired by laser to obtain a flawless smooth surface with surface roughness of 0.731 μm, which provides an effective method for enterprises to repair flywheel disc steel plates.
Investigations on MoS2 plasma by infra-red pulsed laser irradiation in high vacuum
Authors: TORRISI Lorenzo , SILIPIGNI Letteria , TORRISI Alfio , CUTRONEO Mariapompea
Published: March 2024

MoS2 targets were irradiated by infra-red (IR) pulsed laser in a high vacuum to determine hot plasma parameters, atomic, molecular and ion emission, and angular and charge state distributions. In this way, pulsed laser deposition (PLD) of thin films on graphene oxide substrates was also realized. An Nd:YAG laser, operating at the 1064 nm wavelength with a 5 ns pulse duration and up to a 1 J pulse energy, in a single pulse or at a 10 Hz repetition rate, was employed. Ablation yield was measured as a function of the laser fluence. Plasma was characterized using different analysis techniques, such as time-of-flight measurements, quadrupole mass spectrometry and fast CCD visible imaging. The so-produced films were characterized by composition, thickness, roughness, wetting ability, and morphology. When compared to the MoS2 targets, they show a slight decrease of S with respect to Mo, due to higher ablation yield, low fusion temperature and high sublimation in vacuum. The pulsed IR laser deposited MoS
x
(with 1 < x < 2) films are uniform, with a thickness of about 130 nm, a roughness of about 50 nm and a higher wettability than the MoS2 targets. Some potential applications of the pulsed IR laser-deposited MoS
x
films are also presented and discussed.
Revealing precipitation behavior and mechanical response of wire-arc directed energy deposited Mg-Gd-Y-Zr alloy by tailoring aging procedures
Authors: Li Xinzhi , Fang Xuewei , Zhang Zhiyan , Ghafoor Shahid , Chen Ruikai , Liu Yi , Tang Kexin , Li Kai , Ma Minghua , Shang Jiahao , Huang Ke
Published: March 2024

Mg-Gd-Y-Zr alloy, as a typical magnesium rare-earth (Mg-RE) alloy, is gaining popularity in the advanced equipment manufacturing fields owing to its noticeable age-hardening properties and high specific strength. However, it is extremely challenging to prepare wrought components with large dimensions and complex shapes because of the poor room-temperature processability of Mg-Gd-Y-Zr alloy. Herein, we report a wire-arc directed energy deposited (DED) Mg-10.45Gd-2.27Y-0.52Zr (wt.%, GW102K) alloy with high RE content presenting a prominent combination of strength and ductility, realized by tailored nanoprecipitates through an optimized heat treatment procedure. Specifically, the solution-treated sample exhibits excellent ductility with an elongation (EL) of (14.6 ± 0.1)%, while the aging-treated sample at 200 °C for 58 h achieves an ultra-high ultimate tensile strength (UTS) of (371 ± 1.5) MPa. Besides, the aging-treated sample at 250 °C for 16 h attains a good strength-ductility synergy with a UTS of (316 ± 2.1) MPa and a EL of (8.5 ± 0.1)%. Particularly, the evolution mechanisms of precipitation response induced by various aging parameters and deformation behavior caused by nanoprecipitates type were also systematically revealed. The excellent ductility resulted from coordinating localized strains facilitated by active slip activity. And the ultra-high strength should be ascribed to the dense nano-β′ hampering dislocation motion. Additionally, the shearable nano-β
1 contributed to the good strength-ductility synergy. This work thus offers insightful understanding into the nanoprecipitates manipulation and performance tailoring for the wire-arc DED preparation of large-sized Mg-Gd-Y-Zr components with complex geometries.
Principle and verification of behavior model of gate-controlled SCR with adjustable on-resistance
Authors: Bao Xingtao , Wang Yang , Liu Yujie , Jin Xiangliang
Published: March 2024

This paper delineates the implementation of a gate-controlled Silicon Controlled Rectifier (SCR) behavioral model using Cadence software. The model is designed to tackle the absence of gate-control effect characteristics in extant models. This enables more precise simulation of the snapback behavior of such gate-controlled SCR devices under electrostatic discharge (ESD) stress. This work fabricates three types of SCR devices: Traditional SCR(T-SCR), Single-Gate SCR (SG-SCR), and a Double-Gate SCR (DG-SCR). These devices are fabricated using the 0.18 μm CMOS process and varied in the number of gates. The physical principles of the device are validated through two-dimensional electrical simulations. Furthermore, the model results are confirmed by the transmission line pulse (TLP) test results of the final device. The results demonstrate that the simulation results of the gate-controlled SCR behavioral model fit the TLP test results of the three SCR devices. The model’s applicability across different number of fingers devices confirms its scalability. Further, the model was simulated with the HBM equivalent circuit, and the comparison with the actual results confirmed the model’s applicability to HBM simulation.
Material extrusion 3D printing of ceramic structures with overhangs: rheological aspect and introduction of powder-on-demand supporter
Authors: Lee Gyeongyeong , Fernandez Frances Danielle , Kim Jihoon
Published: March 2024

Additive manufacturing (AM), represented as a manufacturing process, which is easily applicable to intricate designs, is widely considered in a variety of industries as a simple and cost-effective solution that complements or replaces traditional manufacturing processes. However, due to the demanding properties of ink materials employing ceramic materials, more stringent considerations are required in selecting an appropriate printing technique and implementing the rheological properties of the ceramic ink suitable for the selected printing technique. Here, material extrusion (ME) was selected as a 3D technique applicable to ceramic materials, and the rheological requirements of ceramic pastes that maximize their printability in ME were scrutinized in detail. It was found that the viscoelastic properties of the ceramic pastes played an important role in determining the flowability, cumulative height, and overhang angles that can be allowed in ME. A new supporter system for overhangs, powder-on-demand supporter (PODS), was introduced to ME and demonstrated to understand if PODS can further extend the limits in cumulative height and overhang angles allowed in ME.
Log-concave polynomials III: Mason’s ultra-log-concavity conjecture for independent sets of matroids
Authors: Anari Nima , Liu Kuikui , Oveis Gharan Shayan , Vinzant Cynthia
Published: March 2024

We give a self-contained proof of the strongest version of Mason’s conjecture, namely that for any matroid the sequence of the number of independent sets of given sizes is ultra log-concave. To do this, we introduce a class of polynomials, called completely log-concave polynomials, whose bivariate restrictions have ultra log-concave coefficients. At the heart of our proof we show that for any matroid, the homogenization of the generating polynomial of its independent sets is completely log-concave.
Accurate Desire
Authors: Hazlett Allan
Published: March 2024

This chapter provides an articulation of the claim that goodness is the accuracy condition for desire, in the same sense that truth is the accuracy condition for belief. A number of assumptions about desire and goodness are stated and motivated, including that desire is propositional and that it makes sense to speak of a state of affairs being good. The existence of “axial gaps”—cases in which something is neither good nor bad—is assumed and the existence of “axial gluts”—cases in which something is both good and bad—is considered. The chapter concludes with a response to a familiar objection to the view that desire is a species of evaluation, on which it is possible to desire something because it is bad.
Introduction
Authors: Bennett Michael Y
Published: March 2024

This Introduction begins with a short reading of Suzan-Lori Parks’ play, Topdog/Underdog, to examine how theatre operates. This short analysis opens up two questions for this book: What is the relationship between theatre’s words and the (conceptual) empty spaces between the lines? and How does this relationship play out with real bodies, in real space, moving through real time, both in performance and in the readers’ imaginations? These questions yield the three main topics for this book: (1) theatre as an art form, (2) the properties of theatrical characters and theatrical worlds, and (3) the difference between truth and truthfulness in the theatre. Ultimately, this book aims to offer the first (contemporary) systematic account of theatret. This Introduction, then, lays out the claims and the scope of the book. It details the organization of the book and provides chapter summaries.
The Nature of Viewing Theatre
Authors: Bennett Michael Y
Published: March 2024

This chapter is concerned with the epistemology of theatre. It streamlines a previously published concept, for this book’s present purposes, of individual and group triangulation that is needed to understand a performance, as witnessed by two or more viewers. It turns to ideas about Bayesian epistemology to explain how different viewers of a performance do not share the same experiences. That is, while performance may be a public event, performance is not a shared individual experience, as viewers not only come in with differing amounts and types of knowledge but will also be looking for different amounts and types of information during the performance. Given the claim that a piece of theatre never really ends, this chapter discusses how theatre is a living document and a malleable idea.
Distinctness in Theatre
Authors: Bennett Michael Y
Published: March 2024

This chapter examines the propositional content of a particular p (e.g., p1, p2, p3 . . .), whether or not it is true, is only understood—and understood to be true—if p1 is uttered in a particular time, place, and situation (i.e., during a theatrical event); otherwise, the propositional content in those theatrical utterances can either be false or contingently true. This chapter also looks at the tense of theatre as being in the past subjunctive. A history play, or a play that invokes historical events, is generally based upon a set of distinct facts, often about an object (often a person) and/or an event. Outside of those, usually quite limited number of distinct facts (dates, names, such and such events, etc.), most of the truthfulness of a play comes from a set of subsumed properties that are not (necessarily) true but display, rather, truthfulness.