bluuebunny/crossref_metadata_2025 huggingface dataset:
Correction: Photoluminescence modification of europium(iii)-doped MAl2O4 (M = Zn, Mg) spinels induced by Ag@SiO2 core–shell nanoparticles
Authors: Valenzuela-Fernández Rodrigo A. , Maine Arianne , Cardin Julien , Portier Xavier , Labbé Christophe , Pinto Cristóbal , Melo Francisco , Pizarro Nancy , Vargas Víctor , Segura Camilo , Galdámez Antonio
Published: July 2024

Correction for ‘Photoluminescence modification of europium(iii)-doped MAl2O4 (M = Zn, Mg) spinels induced by Ag@SiO2 core–shell nanoparticles’ by Rodrigo A. Valenzuela-Fernández et al., Nanoscale, 2024, https://doi.org/10.1039/d4nr01526f.
In(OTf)3-catalyzed formal (4 + 3) cycloaddition reactions of 3-benzylideneindoline-2-thiones with 2-indolylmethanols
Authors: Wang Xue-Long , Yang Yi , Jiang Yan
Published: July 2024

A protocol for the construction of diindole-annulated tetrahydrothiepines via a Lewis acid-catalyzed (4 + 3) cycloaddition reaction is described.
Crystal facet-dependent upgrading of saccharides over barium peroxide to synthesize C-glycoside ketones
Authors: Lu Rui , Chen Hao , Yin Han , Zhang Xi , Lv Songqing , Kong Xiangtao , Lu Fang
Published: July 2024

Crystal facet-dependent Knoevenagel condensation of barium peroxide (BaO2) achieves the efficient construction of C–C bonds of unprotected saccharides to synthesize C-glycosides.
Brønsted base catalyzed Reppe sulfonylation reaction
Authors: He Xiaochun , Wang Xiaohong , Zhou Fei , Song Hongzhuo , Zhang Xuemei , Lian Zhong
Published: July 2024

The Reppe sulfonylation reaction has remained substantially underexplored. We present a novel method for Reppe sulfonylation involving SO2 insertion, remarkably without the need for metal catalysts, instead utilizing Brønsted bases as catalysts.
Exploring dielectric and AC conduction characteristics in elemental selenium glass modified with silver halides
Authors: Kumar Anil , Saraswat Vishnu , Dahshan A. , Elsaeedy H. I. , Mehta Neeraj
Published: July 2024

Schematic illustration of the steps involved in the synthesis route of the present samples by doping of silver halides in glassy Selenium.
Alternative and efficient one-pot three-component synthesis of substituted 2-aryl-4-styrylquinazolines/4-styrylquinazolines from synthetically available 1-(2-aminophenyl)-3-arylprop-2-en-1-ones: characterization and evaluation of their antiproliferative activities
Authors: Rodríguez Diego Fernando , Lipez Kelly Johanna , Stashenko Elena , Díaz Iván , Cobo Justo , Palma Alirio
Published: July 2024

The AcONH4-promoted and catalyst-free one-pot three-component synthesis of diverse substituted 4-styrylquinazolines have been developed from 2′-aminochalcones, aromatic aldehydes/trimethyl orthoformate, and ammonium acetate.
Low power density, high-efficiency reflective Raman system for polymer SERS substrates
Authors: Lin Ding-Zheng , Chang Heng-I. , Tsia Kai-Chun , Chung Yu-Ya
Published: July 2024

The proposed RR system demonstrated its outstanding performance for low damage threshold analytes and SERS substrates, creating more stable and stronger Raman signals under the limitation of low power density input.
Reaction acceleration at the surface of a levitated droplet by vapor dosing from a partner droplet
Authors: Qiu Lingqi , Li Xilai , Holden Dylan T. , Cooks R. Graham
Published: July 2024

Chemical reactions in millimeter-sized droplets can be accelerated by more than an order of magnitude.
Shape equilibria of vesicles with rigid planar inclusions
Authors: Jeon Geunwoong , Fagnoni Justin , Wan Hao , Santore Maria M. , Grason Gregory M.
Published: July 2024

Motivated by recent studies of two-phase lipid vesicles possessing 2D solid domains integrated within a fluid bilayer phase, we study the shape equilibria of closed vesicles possessing a single planar, circular inclusion.
Acetylacetone functionalized periodic mesoporous organosilicas: from sensing to catalysis
Authors: Liu Chunhui , Haghighat Mahdieh , Jena Himanshu Sekhar , Poelman Dirk , De Geyter Nathalie , Morent Rino , Kaczmarek Anna M. , Van Der Voort Pascal
Published: July 2024

“acac-PMO” with the acac-functionality intact and embedded in the organic environment of the linker.
Flexible electrode materials for emerging electronics: materials, fabrication and applications
Authors: Liu Kai , Duan Tianyi , Zhang Fengran , Tian Xiaozhu , Li Hui , Feng Min , Wang Rui , Jiang Benshuai , Zhang Kewei
Published: July 2024

This paper reviews the progress of flexible electrodes in recent years, including flexible substrates, active materials, manufacturing methods, and their latest applications in flexible sensors, flexible energy storage, and medical and healthcare.
Contact-electro-catalysis under natural and industrial conditions: mechanisms, strategies, and challenges
Authors: Li Xinnan , Tong Wangshu
Published: July 2024

The competition between electron transfer and ion transfer at the solid–liquid interface is summarized and the performance improvement strategies of contact-electro-catalysis under natural or industrial conditions are given.
Progress and perspectives on electrocatalytic transmembrane hydrogenation
Authors: Zhou Xianlong , Yu Xi , You Bo , Jing Yu
Published: July 2024

This review summarizes the developments of Pd membrane reactors to drive electrochemical hydrogenation of unsaturated compounds including gaseous reagents. It highlights the design of Pd-based catalysts and their utilization to drive hydrogenation.
Dual regulation of flexible chain segments and dynamic covalent bonds for a self-healable copolyimide
Authors: Liu Huizhu , Wan Baoquan , Wang Jiangqiong , Jiang Xing , Zha Jun-Wei
Published: July 2024

A copolymerized polyimide is prepared by a simple process of combining flexible PDMS chain segments and monomers containing disulfide bonds. The material shows good self-healing ability after mechanical/electrical damage.
Europium–tannic acid nanocomplexes devised for bone regeneration under oxidative or inflammatory environments
Authors: Fernández-Villa Daniel , Aguilar María Rosa , Rojo Luis
Published: July 2024

Anti-inflammatory, antioxidant, and osteogenic effects of Eu3+–tannic acid nanocomplexes (EuTA NCs) designed to promote bone growth in complex environments by simultaneously targeting multiple pathophysiological mechanisms of osteopenia.
Investigating the influence of relative humidity on the hot-air drying mechanism and properties of a double-base propellant
Authors: Meng Derong , Chen Ling , He Weidong
Published: July 2024

The influence of relative humidity on drying characteristics of a double-base propellant is investigated for the first time using a hot-air drying system. Shorter drying time and better quality of propellants dried at 50 °C and 60% relative humidity.
Modulating organic functional groups in stimuli-responsive luminescent antimony chlorides
Authors: Liu Yi , Huang Dan-Dan , Zhang Zhi-Zhuan , Lin Hao-Wei , Du Ke-Zhao , Wang Ze-Ping , Huang Xiao-Ying
Published: July 2024

Stimuli-responsive luminescent antimony-based halides are obtained by designing and synthesizing tunable functionalized organic cations.
Hole-transport materials based on β-cyanodiarylethene core structure for efficient inverted perovskite solar cells
Authors: He Rui , Sun Hao , Zeng Ye , Gao Xing , Yan Tao , Wu Fei , Zhu Linna
Published: July 2024

Three hole-transport materials (MT1–3) were successfully used in inverted perovskite solar cells, and the MT1-based device exhibited excellent efficiency.
Apparatus for swelling deformation of compacted bentonite utilizing multi-ring moulds for evaluation of dry density and water content distribution
Authors: Ito Daichi , Wang Hailong , Komine Hideo
Published: July 2024

In the geological disposal of high-level radioactive waste, bentonite buffer materials are required to have self-sealing property, which is the ability to fill gaps by swelling deformation between the buffer material and the waste containment vessel or surrounding bedrock. Self-sealing property was evaluated based on the pressure generated after the gap filling under the assumption of constant dry density and water content in the specimen and buffer material. On the other hand, it takes tens to hundreds of years for the transitional period until the buffer contacts with groundwater, fills the gap, and the internal state converges to a uniform state. To assess changes more accurately in the condition of the buffer material, it is necessary to evaluate time courses in the density and water content of the buffer material because of groundwater infiltration and swelling deformation. From these, the authors developed an experimental apparatus for swelling deformation of bentonite, which consists of a mould with 2 mm-thick stacked rings. It is aimed to evaluate the distribution of dry density, water content, and degree of saturation inside the specimen by cutting the specimen with a 2 mm thick ring after the end of experiment. In this paper, results of preliminary experiments to confirm the applicability of this apparatus to swelling deformation test of bentonite was firstly described. Then, experiments were conducted on compacted bentonite specimens using this apparatus, and changes in the dry density and water content distribution inside the specimens were evaluated in terms of swelling deformation behaviour.
Observation of the effect of soil-structure boundaries using transparent soil technology
Authors: Yu Guo , Li Yubo , Cui Ying , He Lei
Published: July 2024

The predominance of water flow at strata boundaries often triggers dam and levee failures. However, research on the porosity and water flow at soil-structure boundaries is insufficient despite the fact that the fact that their significant influence on water flows through soil is due to high porosity caused by compaction difficulties in the boundary region. Additionally, observing the interior of soil by conventional experimental methods is challenging, making it difficult to precisely determine the exact differences between the boundary area and surrounding grounds. Therefore, transparent soil techniques were employed to investigate the interior of the soil and the impact of soil-structure boundaries on flow path formation. The experiment identified two critical properties at the soil-structure boundary: relatively high porosity and the maximum average velocity of the fluid during permeability, both occurring at the interface. The good connectivity of the pores at the boundary is due to the barrier effect of the flat wall, which causes water to flow vertically upward along the boundary. In contrast, water flows meanderingly upward in the interior area of the soil, resulting in a two-dimensional movement at the boundary compared to a three-dimensional movement in the interior of the soil.
A systematic approach for conducting and interpreting hydraulic conductivity tests on granular soils under non-isothermal conditions
Authors: Bortolotto Marina S. , Taborda David M.G. , O’Sullivan Catherine
Published: July 2024

Although non-isothermal tests are important for many applications in geotechnical engineering, there is no standard for conducting such tests and interpreting the resulting data. This paper describes the development of a temperature-controlled triaxial apparatus, focussing on its thermal performance, and discusses relevant protocols to perform and interpret hydraulic conductivity tests on granular materials at different temperatures. With the aid of thermal cameras, hot spots on the surface of the equipment and instruments were identified. Subsequent modifications to minimise and mitigate heat reaching volume gauges and pore water pressure transducers were introduced. After modifications to reduce the system’s intrinsic head losses, the thermal expansion of the system proved to be significant and needed to be accounted for avoiding overestimation of thermally-induced mechanical strains. The addition of a new probe at the centre of the specimen allowed the characterisation of the temperature field within the system and specimen, as well as assisting with the identification of thermal equilibrium. Significant drops in temperature were flagged by this probe, though these proved to be unimportant in terms of hydraulic conductivity. The use of the average temperature for each pressure step is advised when a specimen probe is available. Alternatively, the use of target temperatures can be chosen, leading to minor underestimations of the intrinsic permeability.
Early warning of shallow landslides: Monitoring of pre-failure suction-induced deformation
Authors: Coppola Lucia , Reder Alfredo , Tarantino Alessandro , Mannara Giovanni , Pagano Luca
Published: July 2024

Most of the Landslides Early Warning Systems (LEWS) in operation are based uniquely on monitoring rainfall data, limiting their performance due to false alarms generated by rainfall thresholds. The accuracy of LEWS may be remarkably improved by monitoring soil-based variables and the stress-strain response of the ground during intense rainfall events. This paper investigates whether slope pre-failure deformation can be used as an additional precursor of landslide triggering. This further precursor would substantially improve LEWS accuracy, especially if pre-failure deformation is combined with suction monitoring. Some tests were conducted using a small-scale physical model of a slope built with unsaturated volcanic silt subjected to artificial rainfall. A new device named tensio-Inclinometer was developed to monitor simultaneously suction and suction-induced deformation. It combines a conventional tensiometer and an accelerometer installed at the top of the tensiometer shaft. It is shown that pre-failure deformation detected by the tensiometer shaft tilting is a suitable landslide precursor. Moreover, it can provide reliable soil-based thresholds for early warning systems if combined with suction.
State-dependent dilatancy of sand based on hollow cylinder laboratory tests under shear strain cycles
Authors: Knittel Lukas , Tafili Merita
Published: July 2024

The present study is devoted to the investigation of the dilatancy behaviour of a fine sand based on hollow cylinder tests. Medium and dense samples were tested at a constant average γ = 1, 2, 3 and 4%. Dilatancy curves along with shear wave velocity measurements to investigate the influence of the shear strain amplitude γampl in the shear modulus degradation curve are presented and discussed. The measured stress and strain paths were used to compare the performance of four advanced constitutive models especially in describing the dilatancy behaviour of sand. From the perspective of their constitutive equations, the differences between the simulations with various material models are examined. It may be concluded that all four models allow a proper prediction of torsional shear tests as long as a proper calibration of the material parameters is secured.
Linking sand permeability anisotropy to fabric anisotropy via numerical simulation
Authors: Morimoto Tokio , O’Sullivan Catherine , Taborda David M.G.
Published: July 2024

Characterisation of the permeability of soils is of practical importance and, for cohesionless or granular soils, it can be predicted from the void ratio and the particle size distribution (PSD). However, the effect of fabric anisotropy on the permeability is rarely discussed. Restricting consideration to granular (cohesionless) soil, this study combines a variety of numerical methods to investigate (1) how the anisotropy of the permeability evolves as the soil fabric anisotropy evolves in triaxial deformation and (2) establish a link between the anisotropy of the permeability and the fabric anisotropy. The Discrete Element Method (DEM) was employed to create linearly graded virtual samples of spheres (Cu of 1 to 2). Initially isotropic sphere packings were subjected to triaxial compression or triaxial extension up to 30% of absolute axial strain to induce an anisotropic fabric. Pore Network Models (PNMs) present a computationally efficient option for simulation of flow through the pore space. A PNM models fluid flow between pores (nodes) connected by pipes (edges) whose geometry is defined by the topology of the connected pores and the mass balance equation is solved at each pore. After demonstrating the accuracy of the PNM framework adopted here, this contribution presents data from PNM simulations that used the positions of individual particles in the sheared spherical packings as input data. The fabric and permeability anisotropies during triaxial shear deformation were compared at axial strain intervals of 1%. Detailed microscale analyses suggest that the anisotropy in the permeability can be attributed to an increase in the local conductance of fluid pipes in the direction of the major principal stress, which is related to the evolution of the pore topologies during the shear deformation.
Anisotropy and cyclic loading characteristics of a stiff Bolders Bank glacial till at Cowden
Authors: Liu Tingfa , Ushev Emil , Jardine Richard J.
Published: July 2024

Glacial tills are widespread across the world, common in northern Europe and found under the North and Baltic Seas. Their geological and geotechnical characterisation is important to the geotechnical design of a wide range of onshore and offshore structures. This paper reports outcomes from coordinated monotonic small-strain stress probing, cyclic and larger strain triaxial and hollow cylinder apparatus (HCA) testing on a natural low-to-medium plasticity, apparent highly over consolidated, stiff glacial clay till. Monotonic HCA and triaxial experiments investigated the till’s stiffness and shear strength anisotropy from its limited linear elastic range up to ultimate failure, showing that stiffnesses are higher in the horizontal direction than in the vertical and that higher undrained shear strengths develop under “passive” horizontal loading than “active” vertical loading. The cyclic triaxial tests revealed the impact of cycling on effective stress paths and strain development, and cyclic stiffness degradation. Stable, metastable and unstable patterns of behaviour are identified, along with different cyclic failure modes, which are related to the till’s static yielding behaviour. The experiment results provide the basis for developing, testing and calibrating monotonic and cyclic constitutive models and establishing simplified design procedures for piles installed in comparable tills to support offshore energy and other structures.
Liquefaction behaviour of aluminium and plastic rod assemblies using bi-axial apparatus with application of image analysis
Authors: Sukhumkitcharoen Rawiwan , Koseki Junichi , Kyokawa Hiroyuki , Otsubo Masahide
Published: July 2024

It has recently been shown that the overall deformation characteristics of granular materials during liquefaction seems to be governed by local void ratio characteristics. The aim of this study is to investigate the relationship between mechanical properties and local void ratio changes during liquefaction in two materials of different weights (aluminium-type and plastic-type rod assemblies). A series of constant-volume cyclic bi-axial loading tests was conducted together with the image analysis obtaining local void behaviour. The experimental results demonstrate that the first liquefaction resistance of the plastic sample is higher than the aluminium one, corresponding to its smaller initial void ratio and less contractive behaviour observed in the early stage of drained monotonic compression. However, after experiencing the first liquefaction and subsequent re-consolidation histories, a liquefiable assembly of aluminium and plastic rods both became either denser (densification) or more homogenous (homogenization) in terms of local void ratio, suggesting an increase in liquefaction resistance in the next liquefaction stage. This work also includes a preliminary analogous study using a semi-3D discrete element method (DEM) with one single layer of spherical particles to simulate the similar liquefaction behaviour observed in the laboratory tests.
Investigation of shear band strengthening by using different strengthening criteria
Authors: Hadjiloo Elnaz , Grabe Jürgen
Published: July 2024

To prevent a critical failure mechanism, it is possible to simply strengthen the potential shear bands, which is a patented idea. The localization of potential shear bands that are most likely to form shear can be calculated. Before these shear bands can appear, they can be strengthened by injecting a cement suspension or using jet grouting at the locations where the most likely shear bands would occur. As a result, it is possible to increase the bearing capacity of the geotechnical system by focusing solely on the shear bands that are moste likely to form, minimizing the use of materials. Numerical modeling is employed to analyze the increase in bearing capacity. Four criteria for strengthening the shear bands are applied by incorporating them into a hypoplastic soil model, taking into consideration the material transition from soil to cement, as well as intermediate materials that can arise from jet grouting, which are mixtures of soil and cement. Two fundamental geotechnical systems, namely a shallow foundation and a retaining wall, are analyzed using ABAQUS/Standard for finite element analysis. The results demonstrate the potential of numerical modeling to identify the most critical localized areas in the soil that require strengthening, as well as the substantial increase in bearing capacity achieved after reinforcing the identified areas.
On the behavior of compacted filtered iron ore tailings submitted to high pressures
Authors: Silva João Paulo , Carvalho João Vítor , Wagner Alexia Cindy , Consoli Nilo Cesar
Published: July 2024

Mine tailings have been disposed of in a slurry form in tailings dams for many years. However, recent disasters involving conventional disposal in dams reinforced the need for alternative structures to store these materials safely. One alternative is dry stacking of tailings. In these structures, tailings are filtered to low moisture content and then compacted in layers. Due to material compaction, dry stacks tend to be stable and are usually built with elevated heights to use the available area better. So, it becomes essential to understand the mechanical behavior of tailings subjected to high pressures, especially concerning the possibility of grain breakage. In this context, the present research focuses on studying the geotechnical behavior of iron ore tailings from different stages of ore beneficiation plants in Quadrilátero Ferrífero, Brazil, when subjected to high pressures both in compression and in shear paths. The results demonstrate that the inclusion of fines can change the geotechnical performance of the dry stack tailings considering the same compaction energy (greater strength, stiffness, and lower permeability) both in drained and undrained conditions. No breakage could be identified for the stress level studied (6 MPa).
Shear response of iron ore tailings under monotonic loadings
Authors: Medina Guilherme Schmitt , Farenzena Helena Portela , Rodrigues Bráulio Araújo , Silva João Paulo , Festugato Lucas , Consoli Nilo Cesar
Published: July 2024

Dry stacking is a disposition method that is quickly becoming a trend for the mining industry in Brazil. With several cases in which compacted mine tailings are positioned on the top of hydraulically disposed tailings which were placed into pits. The present research assessed the mechanical response of hydraulically disposed iron ore tailings collected from a pit that was formerly a mining site. To better understand the mechanical behaviour of mine tailings under such conditions, the investigation of their monotonic response is of great importance. The studied material was classified as a silty sand with traces of clay size. A very loose condition with distinct confining stresses was tested monotonically on a simple shear equipment. Simple shear tests were performed in an apparatus that can directly measure pore pressure, guaranteeing an effective stresses analysis. A plane strain condition was applied on fully saturated samples under undrained loading conditions. Results showed the agreement of the strength envelopes of monotonic stress paths, the effective friction angle of the material was 33.2° and no cohesive intercept.
Safety assessment in dams due to downstream slope anomalies
Authors: Morandini Thiago , Campos Darym , Ferreira Stéphanie
Published: July 2024

Recent cases of tailings dam failure in Brazil have demonstrated in the current methods of safety assessment of these structures. One of the most employed methods is the evaluation through routine inspections and audits, but this method is considered non-deterministic and affected by the expertise of the evaluator. This paper presents the results of numerical simulations of anomalies commonly found in safety inspections to measure the impact of these anomalies on the dam safety factor. The study was limited to numerical simulations of five types of dams (three downstream and two upstream dams), with varying embankment and tailings strength parameters, simulating different magnitudes of downstream slope anomalies (cracks, scour, and resurgence), totaling a sample space of 270 analyses. The results show that there were average reductions in safety ranging from 4% to 10% for scour simulations, 8% to 25% for resurgence, and 9% to 24% for cracking. The sample standard deviation of the analyses ranged from 8 to 12%. It was also observed that the combined effect of the anomalies showed proportional overlapping effects in reducing the range of safety. It was concluded that the simulated failures are important variables to be evaluated in inspections, not only for demonstrate deviations in the operation and maintenance of structures, but also to predict the magnitude of these failures in dam designs.
Techniques and Surgical Nuances of Management of Comminuted Fronto-Orbital Depressed Fractures: A Single-Surgeon Experience
Authors: Gupta Rahul , Devi B. Indira , Konar Subhas Kanti , Shashidhar Abhinith , Shukla Dhaval
Published: July 2024

Compound fronto-orbital depressed fractures (FODFs) are complex fractures involving the frontal and orbital bones, with associated lacerated wounds on the skin. Repairing such fractures is challenging and requires a multidisciplinary approach. Surgical indications include cerebrospinal fluid rhinorrhea, exposed brain matter, frontal sinus fractures, vision impairment, and cosmetic disfigurement. The repair is typically done using titanium implants (low-profile plates [LPPs] and screws) for a good functional outcome.

In this case series of 10 patients operated by a single surgeon (RG), we present different techniques for repairing FODF. Early surgery (< 48 hours) was performed to minimize infection risk.

Surgical steps included elevation of depressed fragments, dural repair, and reconstruction of orbital walls using LPP. Some cases required inside-out fixation or suture fixation for better alignment of fragments. Autograft was used for severe bone loss.

The results showed good functional outcomes with minimal infection rates. Primary single-stage repair using titanium implants provided satisfactory cosmesis. The use of inside-out repair and sutures was beneficial in specific cases.

In conclusion, primary repair of FODF with titanium implants is safe and effective, reducing morbidity and cost. Early surgery and proper techniques are crucial for successful outcomes. Longer follow-up is needed to assess long-term viability and bone resorption.
Patterns and correlations in European electricity prices
Authors: Trebbien Julius , Tausendfreund Anton , Rydin Gorjão Leonardo , Witthaut Dirk
Published: July 2024

Electricity markets are central to the coordination of power generation and demand. The European power system is divided into several bidding zones, each having an individual electricity market price. While individual price time series have been intensively studied in recent years, spatiotemporal aspects have received little attention. This article provides a comprehensive data-centric analysis of the patterns and correlations of the European day-ahead electricity prices between 2019 and 2023, characteristically abnormal due to the energy crisis in Europe. We identify the dominant communities of bidding zones and show that spatial differences can be described with very few principal components. Most bidding zones in Continental Europe were brought together during the energy crisis: Correlations increased, and the number of relevant principal components decreased. Opposite effects occur in the Nordic countries and the Iberian Peninsula where correlations decrease and communities fragment.
Tuning dissipation dilution in 2D material resonators by MEMS-induced tension
Authors: Wopereis Michiel P. F. , Bouman Niels , Dutta Satadal , Steeneken Peter G. , Alijani Farbod , Verbiest Gerard J.
Published: July 2024

Resonators based on two-dimensional (2D) materials have exceptional properties for application as nanomechanical sensors, which allows them to operate at high frequencies with high sensitivity. However, their performance as nanomechanical sensors is currently limited by their low quality (Q)-factor. Here, we make use of micro-electromechanical systems (MEMS) to apply pure in-plane mechanical strain, enhancing both their resonance frequency and Q-factor. In contrast to earlier work, the 2D material resonators are fabricated on the MEMS actuators without any wet processing steps using a dry-transfer method. A platinum clamp, which is deposited by electron beam-induced deposition, is shown to be effective in fixing the 2D membrane to the MEMS and preventing slippage. By in-plane straining the membranes in a purely mechanical fashion, we increase the tensile energy, thereby diluting dissipation. This way, we show how dissipation dilution can increase the Q-factor of 2D material resonators by 91%. The presented MEMS actuated dissipation dilution method does not only pave the way toward higher Q-factors in resonators based on 2D materials, but also provides a route toward studies of the intrinsic loss mechanisms of 2D materials in the monolayer limit.
Entanglement-enhanced quantum metrology: From standard quantum limit to Heisenberg limit
Authors: Huang Jiahao , Zhuang Min , Lee Chaohong
Published: July 2024

Entanglement-enhanced quantum metrology explores the utilization of quantum entanglement to enhance measurement precision. When particles in a probe are prepared into a suitable quantum entangled state, they may collectively accumulate information about the physical quantity to be measured, leading to an improvement in measurement precision beyond the standard quantum limit and approaching the Heisenberg limit. The rapid advancement of techniques for quantum manipulation and detection has enabled the generation, manipulation, and detection of multi-particle entangled states in synthetic quantum systems such as cold atoms and trapped ions. This article aims to review and illustrate the fundamental principles and experimental progresses that demonstrate multi-particle entanglement for quantum metrology, as well as discuss the potential applications of entanglement-enhanced quantum sensors.
Time- and angle-resolved photoemission spectroscopy with wavelength-tunable pump and extreme ultraviolet probe enabled by twin synchronized amplifiers
Authors: Suzuki Takeshi , Zhong Yigui , Liu Kecheng , Kanai Teruto , Itatani Jiro , Okazaki Kozo
Published: July 2024

We describe a setup for time- and angle-resolved photoemission spectroscopy with wavelength-tunable excitation and an extreme ultraviolet probe. It is enabled by using the 10 kHz twin Ti:sapphire amplifiers seeded by the common Ti:sapphire oscillator. The typical probe energy is 21.7 eV, and the wavelength of the pump excitation is tuned between 2400 and 1200 nm by using the optical parametric amplifier. The spectral width of the extreme ultraviolet probe is 53 meV, and the time resolution is dependent on the wavelength for the pump, better than 60 fs for the pump energy >0.7 eV. This system enables the pump energy to be matched with a specific interband transition and to probe a wider energy-momentum space. We present the results for the prototypical materials of highly oriented pyrolytic graphite and Bi2Se3 to show the performance of our system.
Improvement of linearity in trap-rich substrates for radio frequency applications: Which of donor and acceptor trap is the best?
Authors: Philippe Justine , Robillard Jean-François , Gloria Daniel , Dubois Emmanuel
Published: July 2024

This paper investigates the effect of volume traps intentionally introduced into a silicon-on-insulator (SOI) substrate by inserting a layer of polysilicon beneath buried oxide. In radio frequency applications, this type of substrate, referred to as trap-rich, is known to considerably reduce the generation of harmonics resulting from the parasitic non-linear charge dynamics introduced by the substrate handler under the buried oxide. This analysis focuses on a test vehicle in the form of an integrated coplanar waveguide on two types of substrates, namely, high-resistivity SOI substrates with and without a trap-rich layer. From a modeling point of view, a simulation methodology is implemented in order to convert the 3D simulation of the coplanar waveguide into a 2D treatment that takes into account the wave propagation effect associated with the distributed nature of the transmission line. As a first step, this modeling strategy is implemented to reproduce the effect of increasing substrate resistivity on 2nd and 3rd harmonic reductions, leading to an excellent agreement with experimental data. Building on this validation of the simulation method, we have opted to simulate the non-linear response of the transmission line on the SOI trap-rich substrate by simplifying the trap distribution model. To avoid the adoption of unverified and strongly process-dependent trap distributions across the bandgap, a midgap monovalent trap density has been introduced, either acceptor or donor density. A monovalent density of acceptor traps with a concentration of 1016 cm−3 and a carrier lifetime of 0.1 ns has been shown to reproduce the experimental data very accurately with a substantial reduction in 2nd and 3rd harmonics. A detailed analysis of the displacement current waveforms explains the beneficial role of acceptor traps compared with donor traps.
Transformer oil electrical–thermal characteristics analysis and evaluation
Authors: Luo Yan , Zhou Xiu , Zhu Lin , Bai Jin , Tian Tian , Liu Bo , Zhang Heng
Published: July 2024

Transformer oil plays the role of heat dissipation and insulation in power transformers, and its electrical and thermal characteristics are directly related to the stable operation of the transformer. At the same time, it is important to master the electric–thermal characteristics of transformer oil for transformer state evaluation, latent fault prediction, and maintenance planning. Based on this, the gas production rule and electrical characteristics of transformer oil under accelerated aging are studied in this paper. First, the experimental platform for power transformer aging is established to accelerate the aging of power transformers. Second, the accelerated aging transformer oil is taken as the research object, and the power frequency, DC, lightning, and gas chromatography are measured and analyzed. Finally, a transformer oil aging evaluation model is established, which takes into account four factors: carbon and oxygen gas factors in transformers, life loss factors calculated by hotspot temperature, hydrocarbon gas factors dissolved in transformer oil, and oil quality factors, and conducts aging evaluation. The conclusion shows that the T parameter proposed in this paper can effectively evaluate the quality of transformer oil. When T is less than or equal to 0.6, there is no aging of the oil. When T is greater than 0.6 and less than 1, the transformer oil has been aging, but it is not manifested. Those are parameters whose chromatography and breakdown voltage are not far beyond the IEEE standard. When T = 1, the aging of oil with significant changes in gas content and breakdown voltage can be observed. When T is greater than 1, the oil has undergone serious aging.
Development of a 166.6 MHz β = 1 higher-order-mode-damped superconducting cavity
Authors: Guo Lin , Zhang Pei , Zhang Xinying , Dai Jin , Mi Zhenghui , Ma Qiang , Meng Fanbo
Published: July 2024

The storage ring of the high energy photon source will be driven by five 166.6 MHz β = 1 quarter-wave superconducting cavities operating at 4 K. A higher-order-mode-damped superconducting cavity was designed with excellent rf and mechanical properties based on the successful development of the proof-of-principle cavity. The mechanical design of the dressed cavity was focused on addressing stress safety throughout the processes, tunability, frequency detuning due to pressure fluctuation, and Lorentz force, among other factors. A new liquid helium vessel was designed along with a comprehensive stiffening scheme to mitigate the surging peak stress on the cavity resulting from the significantly unequal beam pipe size. In the first batch, three cavities were manufactured, and surface preparations were carefully conducted to eliminate defects and etching traces while ensuring cleanliness. The cavity’s Q0 at the design voltage of 1.5 MV reached 3.8 × 109 at 4 K, comfortably surpassing the design goal. Field emission onset was not observed during the entire test up to a peak electric field of 60 MV/m, thanks to the optimized processing procedures. Subsequently, one cavity was welded with the newly designed helium vessel and vertically tested at 2 K, achieving an rf performance comparable to the bare cavities, demonstrating the success of the jacketed cavity. This paper presents the design, fabrication, surface preparation, and cryogenic tests of the first higher-order-mode-damped 166.6 MHz β = 1 superconducting cavity.
Enhanced terahertz spin transmittance in the NiO/Pt structure through interface engineering
Authors: Tian Da , Huang Lin , Qiu Hongsong , Zhang Caihong , Wu Jingbo , Fan Kebin , Wu Di , Song Cheng , Jin Biaobing , Chen Jian , Wu Peiheng
Published: July 2024

Since antiferromagnets (AFMs) have the potential to drive spintronic devices to higher speed and stability, generation, and transportation of terahertz (THz) spin currents in AFM/heavy metal (HM) structures have been extensively studied. However, effective methods to optimize the efficiency of THz spin current transmission at the interface are still lacking. Here, we demonstrated a significant enhancement of THz spin current in NiO/Pt structures by using THz emission spectroscopy. The spin transmittance is increased by up to a factor of 3.7 after heating the samples at a temperature of 350 °C for 0.5 h. This enhancement can be attributed to the optimization of the NiO/Pt interface resulting from the heating process. In contrast, the control samples NiO/Cu/Pt and NiO did not exhibit a similar enhancement, indicating that the improvement in spin current transmission is specific to the NiO/Pt interface. The scanning transmission electron microscopy is used to observe the optimized interface and confirmed the reason for THz signal enhancement. Our work paves a way for the modulation of AFM/HM interfaces and the optimization of ultrafast spintronic devices based on AFMs.
Effect of trailing-edge blowing on the acoustic and aerodynamic characteristics of a flatback airfoil
Authors: Guo Jing , Maryami Reza , Wang Jingsong , Wang Xiaoning , Xiang Zilun , Liu Yu
Published: July 2024

This study investigated the impact of trailing-edge uniform air blowing on the acoustic and aerodynamic characteristics of a flatback airfoil. Near- and far-field pressure fluctuations, surface static pressure distribution, as well as boundary layer and wake flow measurements were conducted to comprehensively understand the effects of the method on both the noise generation mechanism and the aerodynamic characteristics of the airfoil. It was revealed that tonal noise originates from surface pressure fluctuations induced by upstream flow disturbances due to vortex shedding. The application of blowing was found to shift large-scale vortices generated during vortex shedding further downstream, resulting in the suppression of surface pressure fluctuations on both the pressure and suction sides of the airfoil, consequently reducing far-field noise. Additionally, blowing enhanced spanwise coherence at the vortex shedding frequency. In terms of aerodynamic behavior, blowing was shown to increase base pressure, leading to drag reduction without affecting lift. Interestingly, the significant drag reduction was found to occur at the same blowing parameter associated with maximum tonal noise reduction.
Universal strain engineering for enhancing the hole mobility and dopability in p-type semiconductors
Authors: Hu Yaoqiao , Cho Kyeongjae
Published: July 2024

Modern electronic and optoelectronic devices rely on the development of the complementary pair of n-type and p-type semiconductors. However, it is often seen that n-type semiconductors are easier to realize and offer superior performances than their p-type counterparts, with p-type semiconductors showing much lower hole mobility and inefficient carrier doping. Here, by using first-principles studies, we demonstrate that lattice strain engineering can be a universal approach to enhance the hole mobility and dopability in p-type semiconductors. A broad class of p-type semiconductors, including anion p orbital derived valence band compounds (nitrides, oxides, halides, and chalcogenides), s orbital based post-transition metal oxides (e.g., SnO), and d-orbital based transition metal oxides (e.g., NiO), have been applied on strain to demonstrate their valence band modulation ability for the purpose of increasing the hole mobility and p-type dopability. We show that compressive lattice strain generally results in an upshifted valence band edge and reduced effective hole mass, leading to enhanced p-type dopability and increased hole mobility. Our work highlights strain engineering as a universal and effective approach for achieving better performed p-type compound semiconductors.
The intruder motion in a cubic granular container
Authors: Li Tuo , Cheng Ke , Hou Meiying , Wu Jinze , Wang Siqiang , Ji Shunying , Wang Yujie , Peng Zheng , Yang Hui
Published: July 2024

The Brazil nut effect is a key issue impeding the uniform distribution of particles in a mixed granular system. Extensive research was conducted on this segregation phenomenon in the 1990s and 2000s to identify the mechanisms and influencing factors involved. However, due to limitations in experimental techniques, the scope and effectiveness of research have been restricted. In this study, the Hall-effect magnetic sensing technique was utilized to track the motion of a single magnetic sphere (referred to as the intruder) within a cubic granular bed. This tracking method allowed for the measurement of the intruder's equilibrium positions as well as its trajectories. In a vibration-fluidized cubic granular container, an interesting phenomenon was observed: the intruder displayed a unique periodic helical oscillatory motion near the corner of the cubic container, with the oscillation amplitude gradually attenuating until stabilizing at its equilibrium position. A discrete element method simulation was carried out, revealing that the granular convection flow ascends from the center and descends near the container walls, with a faster flow rate at the four corners. An equation of motion was established accordingly for an intruder in such a convective granular flow, providing a comprehensive explanation for the observed intruder behavior. As a result of this comprehensive approach, we have uncovered the unique phenomenon of different mechanisms collectively driving the periodic spiral oscillation of the intruder before it eventually rested in its equilibrium position, a phenomenon whose mechanism has not previously been investigated in the literature.
Observation of strong in-plane perpendicular electric field in a radio frequency plasma with a time-varying magnetic nozzle
Authors: Sekine Hokuto , Koizumi Hiroyuki , Komurasaki Kimiya
Published: July 2024

The spatiotemporal evolution of the electron temperature and plasma potential in a 200-W radio frequency argon discharge with a time-varying (approximately 60 kHz) magnetic nozzle was measured. Unlike in conventional static magnetic nozzles, the two-dimensional profiles of the electron temperature and plasma potential changed in sync with the applied azimuthal electric field, not with the magnetic field. The temporally resolved electric field vectors demonstrated an enhancement of the perpendicular component, where the direction fairly matched that of electron Eθ×B drift, indicating a space charge separation. This observation suggests that the applied time-varying field actively enhanced cross field electron transport, resulting in a unique potential structure and charged particle acceleration.
A method for calculating two-phase equilibrium: Constrained gray prediction evolutionary algorithm with a surrogate model based on quadratic interpolation
Authors: Shen Yuwei , Hu Zhongbo , Hu Fugao , Su Qinghua , Kou Jisheng
Published: July 2024

Traditional methods, including direct solution methods based on Newton's method and indirect solution methods based on thermodynamic principles, are the mainstream methods used to solve the volume-temperature flash calculation (called NVT-flash), even though they suffer from drawbacks such as sensitivity to initial value and complexity of derivative calculations. A constrained backtracking search algorithm (CBSA), proposed in 2024, was the first and only metaheuristic algorithm to successfully tackle the NVT-flash problem, which overcomes shortcomings of traditional methods. Considering the advantages of metaheuristic algorithms, a constrained gray prediction evolutionary algorithm with a surrogate model based on quadratic interpolation (CGPE-QI) is proposed in this paper to deal with the NVT-flash problem. CGPE-QI considers total Helmholtz free energy as the objective function, moles vector, and volume of a single phase as variables. Constraints to solve the NVT-flash problem are addressed by using a direct search method and an exterior point method. Numerical experiments on two-phase equilibrium of pure substance and mixtures are carried out employing CGPE-QI. Experimental results are the same as those obtained by traditional methods, which confirms that CGPE-QI can effectively tackle the NVT-flash problem and possesses energy decay property. In particular, the results demonstrate that CGPE-QI is more competitive than CBSA in terms of convergence speed, stability, and calculation cost. CGPE-QI proposed in this paper is the second metaheuristic algorithm to successfully solve the NVT-flash problem, illustrating that metaheuristic algorithms have great potential in solving phase equilibrium calculation problems.
High-resolution, highly monochromatic, time-framed, x-ray-backlit-imaging diagnostics with dual-channel toroidal crystals
Authors: Du Huiyao , Si Haoxuan , Jiang Li , Yi Shengzhen , Wang Zhanshan , Dong Jiaqin
Published: July 2024

Here, we developed a high-resolution, dual-channel toroidal-crystal x-ray imager for time-framed x-ray backlit imaging diagnostics using the 4.727 keV helium-like Ti line. We also presented a method for adjusting the dual-channel imager through the self-imaging of a two-dimensional periodic object. Offline x-ray experiments achieved a spatial resolution of ∼5.0 μm in the center and better than 8.0 μm within a field of view (FOV) of ∼2 mm. At the ShenGuang-III prototype laser facility, we obtained imaging results with a spatial resolution of better than 5 μm within an FOV of ±40 µm. This imager thus provides a way of observing with high spatial, temporal, and spectral resolutions to diagnose the behavior of laser-produced plasma.