bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantifying carrier density in monolayer MoS2 by optical spectroscopy
Authors: Myers Alexis R. , Sulas-Kern Dana B. , Fei Rao , Ghoshal Debjit , Hermosilla-Palacios M. Alejandra , Blackburn Jeffrey L.
Published: July 2024

The successful design and device integration of nanoscale heterointerfaces hinges upon precise manipulation of both ground- and excited-state charge carrier (electron and hole) densities. However, it is particularly challenging to quantify these charge carrier densities in nanoscale materials, leading to uncertainties in the mechanisms of many carrier density-dependent properties and processes. Here, we demonstrate a method that utilizes steady-state and transient absorption spectroscopies to correlate monolayer MoS2 electron density with the easily measured metric of excitonic optical absorption quenching in a variety of mixed-dimensionality s-SWCNT/MoS2 heterostructures. By employing a 2D phase-space filling model, the resulting correlation elucidates the relationship between charge density, local dielectric environment, and concomitant excitonic properties. The phase-space filling model is also able to describe existing trends from the literature on transistor-based measurements on MoS2, WS2, and MoSe2 monolayers that were not previously compared to a physical model, providing additional support for our method and results. The findings provide a pathway to the community for estimating both ground- and excited-state carrier densities in a wide range of TMDC-based systems.
Luminescent fiber UV detection
Authors: Li Zeliu , Ren Jiamai , Song Ying , Yan Wen , Zhang Fenglin , Li Xiaotong , Li Ang , Wang Yisong , Zhang Xinpu , Peng Wei
Published: July 2024

Herein, a luminescent fiber device for detecting ultraviolet (UV) intensity, which comprises a UV probe and a photoelectric converter, is proposed. The UV probe consists of a glass tube filled with luminescent material, which can be used for the efficient radiation conversion of UV radiation to the visible spectral region. The luminescent material, Y2O2S:Eu3+, is mixed with polydimethylsiloxane (PDMS) to form the core of the UV probe. Subsequently, the UV radiation response of the luminescent fiber device is investigated; the experimental results demonstrate that the direction-independent UV detection can be realized by using this luminescent fiber UV detection device while UV light is radiated radially along the UV probe. In addition, since partial discharge (PD) is accompanied by UV radiation, we hope to develop a spectral PD detection scheme based on optical fiber technology, which can broaden the role of optical technology and optical fiber technology in the field of PD detection.
Influence of atomistic features in plasmon–exciton coupling and charge transfer driven by a single molecule in a metallic nanocavity
Authors: Candelas Bruno , Zabala Nerea , Koval Peter , Babaze Antton , Sánchez-Portal Daniel , Aizpurua Javier
Published: July 2024

When an organic molecule is placed inside a plasmonic cavity formed by two metallic nanoparticles (MNP) under illumination, the electronic excitations of the molecule couple to the plasmonic electromagnetic modes of the cavity, inducing new hybrid light–matter states called polaritons. Atomistic ab initio methods accurately describe the coupling between MNPs and molecules at the nanometer scale and allow us to analyze how atomistic features influence the interaction. In this work, we study the optical response of a porphine molecule coupled to a silver nanoparticle dimer from first principles, within the linear-response time-dependent density functional theory framework, using the recently developed Python Numeric Atomic Orbitals implementation to compute the optical excitations. The optical spectra show the splitting of the resonances of the plasmonic dimer and the molecule into two distinct polaritons, a characteristic feature of the strong light–matter coupling regime. Our results stress the importance of atomistic features, such as the gap configuration in determining the plasmon–exciton coupling strength and in the emergence of molecule-mediated charge-transfer plasmon (CTP) resonances at lower frequencies. Moreover, we show that the strength of the CTP resonance can be tuned by shifting the alignment of the molecular energy levels with respect to the Fermi level of the MNPs.
A reasonable method to reduce the volume of the WC anvil
Authors: Wang Shengxue , Zhou Hao , Yang Zhenze , Teng Yu , Zhao Hongyu , Ma Hongan , Jia Xiaopeng
Published: July 2024

With the continuous development of the diamond industry, the China-type cubic press (CCP) has gradually become larger. As a result, the volume of the tungsten carbide (WC) anvil has been increased. Considering that the WC anvil is sintered, a larger volume will deteriorate sintering quality, which could facilitate the formation of cracks during its operation. One feasible way to reduce the volume of the WC anvil is to decrease its diameter and height. Along these lines, in this work, by performing finite element simulations, it was found that a reduction in the diameter of the WC anvil would increase the von Mises stress (VMS) during the synthesis process, as well as reduce the service life of the WC anvil and the ultimate pressure of the CCP. At the same time, a smaller diameter of the WC anvil would cause a significant increase in the VMS of the base steel block, exceeding its yield limit. In addition, a reduction in the height of the WC anvil would lessen the VMS during the synthesis process, and the VMS of the base steel block will also decrease. A reduction in the height of the WC anvil will decrease the pretightening force on the WC anvil, thereby reducing its lateral support effect. When the interference fit was increased from 0.6 to 0.8 mm and the steel ring angle was changed from 1.5° to 1.1°, the pretightening force on the low WC anvil was similar to the pretightening force on the original WC anvil. Our work provides valuable insights for effectively reducing the volume of the WC anvil.
Quantitative analysis of atomic migration in lithium-ion conducting oxide solid electrolytes
Authors: Hu Xiangchen , Shi Hongsheng , Wu Xiaoyan , Wang Zeyu , Yu Yi
Published: July 2024

Direct observation of intrinsic atom migration inside bulk materials is crucial for understanding the ion-conducting property; however, microscopy experiments remain challenging. Here, intrinsic atom migration in bulk lithium-ion conductor La2/3–xLi3xTiO3 was investigated by using aberration-corrected transmission electron microscopy. The atomic migration was triggered by high-energy electron beam irradiation. Through quantitative analysis of high-angle annular dark-field image sequences and estimation of random errors using the 3σ criterion, the subtle contrast variation caused by single atom migration was extracted, in which the validity was further confirmed by image simulations. It provides a simple and feasible methodology for investigating the mechanism of atomic migration in bulk materials.
AC metrology applications of the Josephson effect
Authors: Benz S. P. , Biesecker J. , Burroughs C. J. , Castellanos-Beltran M. A. , Dresselhaus P. D. , Flowers-Jacobs N. E. , Fox A. E. , Hopkins P. F. , Johnson-Wilke R. , Olaya D. , Rüfenacht A. , Sirois A. J. , Thomas J. N.
Published: July 2024

The performance of programmable voltage signals that exploit the quantum behavior of superconducting Josephson junctions continues to improve and enhance measurements in metrology, communications, and quantum control. We review advances in pulse-driven digital synthesis techniques with Josephson-junction-based devices. Quantum-based synthesis of voltage waveforms has been demonstrated at frequencies up to 3 GHz and rms amplitudes up to 4 V. Josephson pulse generators have also been used to control and characterize superconducting qubits.
Broadband achromatic thermal metalens with a wide field of view based on wafer-level monolithic processes
Authors: Chen Yen-Chun , Hsu Wei-Lun , Zeng Qiu-Chun , Yu Chen-Yi , Chen Pin-Do , Chen Che-Chin , Lin Yu-Hsin , Chen Fong-Zhi , Wang Chih-Ming
Published: July 2024

We present a monolithic metalens free of chromatic aberration over the 8–12 μm wavelength range for thermal imaging. The metalens consists of nano-donut-pillars for dispersion engineering. The proposed metalens design is based on a telecentric optical system, which effectively eliminates off-focus distortion and aberration, enhancing overall imaging quality. Offering a 90° field of view, the metalens ensures uniform focal spot sizes within a 45° field angle across the working wavelength. This enables the capture of high-quality thermal images with sharp images and minimal distortion. With a diameter of 5.75 mm, the metalens is suitable for integration into commercial thermal imaging cameras. The nano-donut-pillar structure of the metalens allows for relatively straightforward mass production, involving i-line stepper lithography and silicon deep etching processes.
Molecular beam epitaxy growth and doping modulation of topological semimetal NiTe2
Authors: Zhang Liguo , Zhao Dapeng , Liu Xiangyang , Lai Junwen , Ren Junhai , Wang Qin , Lin Haicheng , Sun Yan , Tanigaki Katsumi
Published: July 2024

In this study, high-quality thin films of the topological semimetal phase NiTe2 were prepared using the molecular beam epitaxy technique, confirmed through x-ray diffraction with pronounced Laue oscillations. Electrical transport experiments reveal that thick films have properties similar to bulk materials. By employing co-deposition, we introduced either magnetic or non-magnetic elements during the growth of thinner films, significantly altering their electrical properties. Notably, the magnetic element Cr induces long-range ferromagnetic ordering, leading to the observation of a significant anomalous Hall effect in NiTe2 thin films. The Hall conductivity remains nearly constant well below the Curie temperature, indicating the correlation with the intrinsic topological nature of the band structure. Theoretical first principles band calculations support the generation of the Weyl semimetal state in the material through magnetic doping. These findings pave the way for exploring more magnetic Weyl semimetals and related low-dimensional quantum devices based on topological semimetals.
A sulfur-infiltrated mesoporous silica/CNT composite-based functional interlayer for enhanced Li–S battery performance
Authors: Liang Xiaoru , Lin Zheng , Lin Zhan , Luo Qingyuan , Liang Weihai , Chen Chao
Published: July 2024

The design and construction of functional interlayers for lithium–sulfur (Li–S) batteries has attracted much attention and was demonstrated to be effective to alleviate the notorious “shuttle effect.” An often neglected issue is that the introduction of interlayer will reduce the overall energy density of the battery. In this work, we report a sulfur-infiltrated mesoporous silica/carbon nanotube (CNT) composite as an interlayer for Li–S batteries. The mesoporous silica with large surface area (842 m2 g−1) and pore volume (0.85 cm3 g−1) can not only ensure abundant exposed sites for polysulfide capture but also accommodate a large amount of sulfur inside the pore structure. CNT was composited with silica to enhance the electronic conductivity of the interlayer, which is beneficial for fast sulfur redox reaction kinetics and improved utilization of sulfur. Compared to the pristine and CNT-modified separator, the mesoporous silica/CNT composite-modified separator enables better cycling stability and rate performance. More importantly, it was demonstrated that separately incorporating sulfur into a cathode and interlayer enables better battery performance than locating all the sulfur in the cathode. At a total sulfur loading of 4 mg cm−2 (3 mg cm−2 sulfur on the cathode and 1 mg cm−2 on the mesoporous silica/CNT interlayer), a high initial discharge capacity of 1410 mAh g−1 and a retained capacity of 952 mAh g−1 after 100 cycles were exhibited. This work provides important guidance for future design of functional interlayers for practical Li–S batteries.
Structures of trehalose-6-phosphate synthase, Tps1, from the fungal pathogen
Cryptococcus neoformans
: A target for antifungals
Authors: Washington Erica J. , Zhou Ye , Hsu Allen L. , Petrovich Matthew , Tenor Jennifer L. , Toffaletti Dena L. , Guan Ziqiang , Perfect John R. , Borgnia Mario J. , Bartesaghi Alberto , Brennan Richard G.
Published: July 2024

Invasive fungal diseases are a major threat to human health, resulting in more than 1.5 million annual deaths worldwide. The arsenal of antifungal therapeutics remains limited and is in dire need of drugs that target additional biosynthetic pathways that are absent from humans. One such pathway involves the biosynthesis of trehalose. Trehalose is a disaccharide that is required for pathogenic fungi to survive in their human hosts. In the first step of trehalose biosynthesis, trehalose-6-phosphate synthase (Tps1) converts UDP-glucose and glucose-6-phosphate to trehalose-6-phosphate. Here, we report the structures of full-length
Cryptococcus neoformans
Tps1 (CnTps1) in unliganded form and in complex with uridine diphosphate and glucose-6-phosphate. Comparison of these two structures reveals significant movement toward the catalytic pocket by the N terminus upon ligand binding and identifies residues required for substrate binding, as well as residues that stabilize the tetramer. Intriguingly, an intrinsically disordered domain (IDD), which is conserved among Cryptococcal species and closely related basidiomycetes, extends from each subunit of the tetramer into the “solvent” but is not visible in density maps. We determined that the IDD is not required for
C. neoformans
Tps1-dependent thermotolerance and osmotic stress survival. Studies with UDP-galactose highlight the exquisite substrate specificity of CnTps1. In toto, these studies expand our knowledge of trehalose biosynthesis in
Cryptococcus
and highlight the potential of developing antifungal therapeutics that disrupt the synthesis of this disaccharide or the formation of a functional tetramer and the use of cryo-EM in the structural characterization of CnTps1–ligand/drug complexes.
A Markovian dynamics for
Caenorhabditis elegans
behavior across scales
Authors: Costa Antonio C. , Ahamed Tosif , Jordan David , Stephens Greg J.
Published: July 2024

How do we capture the breadth of behavior in animal movement, from rapid body twitches to aging? Using high-resolution videos of the nematode worm
Caenorhabditis elegans
, we show that a single dynamics connects posture-scale fluctuations with trajectory diffusion and longer-lived behavioral states. We take short posture sequences as an instantaneous behavioral measure, fixing the sequence length for maximal prediction. Within the space of posture sequences, we construct a fine-scale, maximum entropy partition so that transitions among microstates define a high-fidelity Markov model, which we also use as a means of principled coarse-graining. We translate these dynamics into movement using resistive force theory, capturing the statistical properties of foraging trajectories. Predictive across scales, we leverage the longest-lived eigenvectors of the inferred Markov chain to perform a top–down subdivision of the worm’s foraging behavior, revealing both “runs-and-pirouettes” as well as previously uncharacterized finer-scale behaviors. We use our model to investigate the relevance of these fine-scale behaviors for foraging success, recovering a trade-off between local and global search strategies.
Planet in danger! Climate emotions in English
Authors: Bromhead Helen
Published: July 2024

People can respond to the planet in danger through emotions. In English, some of the most common emotional
reactions to the climate crisis have been labelled with terms such as eco-anxiety, climate
grief and ecological distress. This chapter takes the popular, rather than academic, reception
of these emotion terms based on a collection of English-language podcasts. As a cultural pragmatics study, its method is
semantically-enhanced discourse studies, which draws on natural semantic metalanguage (NSM) approach. Through examination of
popular discussions of climate emotions, which show some diversity of opinion, the chapter moves to put forward an emotion
model for overarching relevant ecological feelings and an action model for a typical motivation of School Strikers. These
models constitute two innovative representations arising from semantically-enhanced discourse studies. The chapter ends with
some proposals for how to study the pragmatics of emotions and how to work with novel, often environmental, vocabulary for
which fixed senses have not settled.
A three-way organelle junction controls PI(4)P metabolism and mitochondrial division
Authors: Posor York , Haucke Volker
Published: July 2024

Membrane contact sites (MCS) facilitate communication between organelles. Casler et al. (https://doi.org/10.1083/jcb.202308144) show that tripartite MCS between mitochondria, the endoplasmic reticulum (ER), and the plasma membrane (PM) regulate mitochondrial division and the distribution of phosphatidylinositol 4-phosphate [PI(4)P] on the PM.
Mechanisms of a novel regulatory light chain–dependent cardiac myosin inhibitor
Authors: Kooiker Kristina , Gan Qing-Fen , Yu Ming , Sa Na , Mohran Saffie , Cheng Yuanhua , Flint Galina , Neys Stephanie , Gao Chengqian , Nissen Devin , McMillen Tim , Asencio Anthony , Ma Weikang , Irving Thomas C. , Moussavi-Harami Farid , Regnier Michael
Published: July 2024

Hypertrophic cardiomyopathy (HCM) is a genetic disease of the heart characterized by thickening of the left ventricle (LV), hypercontractility, and impaired relaxation. HCM is caused primarily by heritable mutations in sarcomeric proteins, such as β myosin heavy chain. Until recently, medications in clinical use for HCM did not directly target the underlying contractile changes in the sarcomere. Here, we investigate a novel small molecule, RLC-1, identified in a bovine cardiac myofibril high-throughput screen. RLC-1 is highly dependent on the presence of a regulatory light chain to bind to cardiac myosin and modulate its ATPase activity. In demembranated rat LV trabeculae, RLC-1 decreased maximal Ca2+-activated force and Ca2+ sensitivity of force, while it increased the submaximal rate constant for tension redevelopment. In myofibrils isolated from rat LV, both maximal and submaximal Ca2+-activated force are reduced by nearly 50%. Additionally, the fast and slow phases of relaxation were approximately twice as fast as DMSO controls, and the duration of the slow phase was shorter. Structurally, x-ray diffraction studies showed that RLC-1 moved myosin heads away from the thick filament backbone and decreased the order of myosin heads, which is different from other myosin inhibitors. In intact trabeculae and isolated cardiomyocytes, RLC-1 treatment resulted in decreased peak twitch magnitude and faster activation and relaxation kinetics. In conclusion, RLC-1 accelerated kinetics and decreased force production in the demembranated tissue, intact tissue, and intact whole cells, resulting in a smaller cardiac twitch, which could improve the underlying contractile changes associated with HCM.
The mechanism of tuning filler orientation degree in composites based on AC electric field assist: from microscopic dynamical model to macroscopic electrical properties
Authors: Yao Huanmin , Mu Haibao , Li He , Qian Zhiyuan , Liu Chengshan , Li Wendong , Zhang Daning , Zhang Guanjun
Published: July 2024

Using the AC electric field to induce the orientation of nonlinear conductive fillers in composites is an effective solution for alleviating electric field distortion in power modules. However, the mechanism by which the electric field affects the filler dynamic characteristics and the composites’ electrical properties remains unclear. In this paper, the correlation between the microscopic dynamic processes of fillers and the macroscopic current amplitude was analyzed. The results show that the current increases rapidly (0 ∼ 173 s) and then slowly (173 ∼ 869 s) at 600 V mm−1, influenced by the rotation and attraction processes of the fillers. This demonstrates that the orientation stops at about 869 s and the filler orientation state is a key factor in determining the dielectric properties. Secondly, the global orientation evaluation index D for the filler network was proposed, which can also derive the minimum time and energy loss required for preparation. Finally, the impact of different filler orientations on the composites’ conductivity was investigated. In the low electric field stress region, with the average carrier jump distance decreasing from 150.23 to 109.71 nm as the D increases from −0.93 to −0.05. On this basis, materials with nonlinear conductivity gradient distribution can be easily prepared. Before optimization, the electric field stress of the power module at the triple point was 35.79 kV. This composite can reduce the value to 15.42 kV, a decrease of 56.9%, while maintaining good electric field uniformity.
Effects of vacancy defects and atomic doping on the electronic and magnetic properties of puckered penta-like PdPSe monolayer: an Ab initio study
Authors: Bafekry A , Faraji M , Abdolahzadeh Ziabari A , Javad Musavi S , Fadlallah M M , Ghergherehchi M , Soo Chang Gap
Published: July 2024

The experimental knowledge of two-dimensional penta-like PdPSe monolayer is largely based on a recent publication (Li et al 2021 Adv. Mater. 2102541). Therefore, the aim of our research is consequently to explore the effect of vacancy defects and substitutional doping on the electronic properties of the novel penta-PdPSe monolayer by using first-principles calculations. Penta-like PdPSe is a semiconductor with an indirect bandgap of 1.40 eV. We show that Pd and Se vacancy defected structures are semiconductors with band gaps of 1.10 eV and 0.95 eV respectively. While P single vacancy and double vacancy defected structures are metals. The doping with Ag (at Pd site) and Si (at P site) convert the PdPSe to nonmagnetic metallic monolayer while the doping with Rh (at Pd site), Se (at P site) and As (at site Se) convert it to diluted magnetic semiconductors with the magnetic moment of 1 µ

B
. The doping with Pt (at the Pd site), As (at the P site), S and Te (at Se site) are indirect semiconductors with a bandgap of ∼1.2 eV. We undertook this theoretical study to inspire many experimentalists to focus on penta-like PdPSe monolayer growth incorporating different impurities and by defect engineering to tune the novel two dimensional materials (PdPSe) properties for the advanced nanoelectronic application.
Ferroelectricity-controlled magnetic ordering and spin photocurrent in NiCl2/GeS multiferroic heterostructures
Authors: Arora Anu , Nandi Pradip , De Sarkar Abir
Published: July 2024

Controlling magnetism solely through electrical means is indeed a significant challenge, yet holds great potential for advancing information technology. Herein, our investigation presents a promising avenue for electrically manipulating magnetic ordering within 2D van der Waals NiCl2/GeS heterostructures. These heterostructures, characterized by their unique magnetic-ferroelectric (FE) layer stacking, demonstrate spin-constrained photoelectric memory, enabling low-power electrical writing and non-destructive optical reading. The two orientations of the polarization in the GeS FE layer bring about changes in the ground state configuration, transitioning from ferromagnetic (FM) to antiferromagnetic (AFM) orderings within the NiCl2 magnetic layer. Correspondingly, the light-induced charge transfer prompts either spin-polarized or unpolarized currents from the FM or AFM states, serving as distinct ‘1’ or ‘0’ states, and facilitating applications in logic processing and memory devices. This transition stems from the interplay of interfacial charge transfer mechanisms and the influence of the effective electric field (E
eff), bringing a non-volatile electric enhancement in the magnetic anisotropy energy within the NiCl2/GeS heterostructure. Overall, our study highlights the NiCl2/GeS heterostructure as an optimal candidate for realizing spin-dependent photoelectric memory, offering unprecedented opportunities for seamlessly integrating memory processing capabilities into a single device through the utilization of layered multiferroic heterostructures.
Eliminating thermal responses of stay cables by partially missing sensors toward more reliable and robust SHM
Authors: Chen Si-Xin , Lin Wei-Qiang , Zhu Zhi-Wen
Published: July 2024

In structural health monitoring (SHM), data normalization is important since the features sensitive to potential damages may be buried by the operational and environmental effects. Although cables are critical components in cable-stayed bridges, their temperature effects have not been sufficiently studied. To bridge this gap, this study proposed a framework to capture and eliminate the thermal response (TR) of cable forces to enhance the reliability of SHM. Specifically, empirical wavelet transform was used to approximate the TR, and gated recurrent unit was used to learn to infer the TR based on field monitored temperature field (TF) data. In addition, a recovery mechanism called generative adversarial imputation nets (GAIN) was introduced to recover the TF from partial sensors to enhance the robustness of this method. Four cables of a bridge, covering long or short, side span or midspan, are investigated. Results show that the developed model can well capture the TR, which contributes to 63%–93% of the total variation of cable forces. By eliminating the TR, the entropy can be reduced by 19%–43% and obtain 0.7–1.4 bits. It is also shown that the introduction of GAIN makes the sensing of TF robust to sensor missing, even when the missing ratio reaches 28.6%, and thus makes the TR inference robust. It is expected that this study can bring more reliable and robust SHM for critical infrastructures.
Ultrathin In2O3 thin-film transistors deposited from trimethylindium and ozone
Authors: Zhu Jianzhang , Li Jinxiong , Ju Shanshan , Lu Lei , Zhang Shengdong , Wang Xinwei
Published: July 2024

Indium oxide (In2O3) is a promising channel material for thin-film transistors (TFTs). In this work, we develop an atomic layer deposition (ALD) process of using trimethylindium and ozone (O3) to deposit In2O3 films and fabricate ultrathin In2O3 TFTs. The In2O3 TFTs with 4 nm channel thickness show generally good switching characteristics with a high I
on/I
off of 108, a high mobility (μ
FE) of 16.2

c

m

2

V

−
1

s

−
1

and a positive threshold voltage (V
th) of 0.48 V. Although the 4 nm In2O3 TFTs exhibit short channel effect, it can be improved by adding an ALD Ga2O3 capping layer to afford the bilayer In2O3/Ga2O3 channel structure. The afforded In2O3/Ga2O3 TFTs exhibit improved immunity to the short channel effect, with good TFT characteristics of I
on/I
off of 107, μ
FE of 9.3

c

m

2

V

−
1

s

−
1

, and positive V
th of 2.23 V. Overall, the thermal budget of the entire process is only 400 °C, which is suitable for the display and CMOS back-end-of-line-compatible applications.
G band enhancement in ABt-twisted trilayer graphene
Authors: Luo Ronghui , Li Xiaofeng , Li Xiao , Liu Zhibo
Published: July 2024

G band, originating from the in-plane vibrations of carbon atoms, is the main signature in Raman spectroscopy of graphene-based systems. It is often used to characterize the sample quality and obtain molecular vibration information. Here we investigate the Raman spectroscopy of ABt-twisted trilayer graphene (ABt-TTG) and observe two enhancement centers for the G band across samples with different twist angles. To understand the origin of these two enhancement centers, we theoretically calculate the G band intensity of ABt-TTG based on the continuum model. We find that the theoretical calculations exhibit two prominent peaks corresponding to the experimental observations after Fermi velocity corrections. We also investigated the real and imaginary parts of Raman resonances, respectively, and explained the origins of two enhancements of ABt-TTG. By using Raman spectroscopy, evolutions of band structures of ABt-TTG with respect to the twist angles can be characterized, which extends the potential applications of the Raman method in the investigation of electronic structures of graphene-based systems.
Commissioning an ultra-high-dose-rate electron linac with end-to-end tests
Authors: Dai Tianyuan , Sloop Austin M , Ashraf Muhammad R , Sunnerberg Jacob P , Clark Megan A , Bruza Petr , Pogue Brian W , Jarvis Lesley , Gladstone David J , Zhang Rongxiao
Published: July 2024

Objective. The FLASH effect can potentially be used to improve the therapeutic ratio of radiotherapy (RT) through delivery of Ultra-high-dose-rate (UHDR) irradiation. Research is actively being conducted to translate UHDR-RT and for this purpose the Mobetron is capable of producing electron beams at both UHDR and conventional dose rates for FLASH research and translation. This work presents commissioning of an UHDR Mobetron with end-to-end tests developed for preclinical research. Approach. UHDR electron beams were commissioned with an efficient approach utilizing a 3D-printed water tank and film to fully characterize beam characteristics and dependences on field size, pulse width (PW) and pulse repetition frequency (PRF). This commissioning data was used to implement a beam model using the GAMOS Monte Carlo toolkit for the preclinical research. Then, the workflow for preclinical FLASH irradiation was validated with end-to-end tests delivered to a 3D-printed mouse phantom with internal inhomogeneities. Main results. PDDs, profiles and output factors acquired with radiochromic films were precisely measured, with a PRF that showed little effect on the UHDR beam energy and spatial characteristics. Increasing PW reduced the D
max and R50 by 2.08 mm µs−1 and 1.28 mm µs−1 respectively. An end-to-end test of the preclinical research workflow showed that both profiles in head-foot and lateral directions were in good agreement with the MC calculations for the heterogeneous 3D printed mouse phantom with Gamma index above 93% for 2 mm/2% criteria, and 99% for 3 mm/3%. Significance. The UHDR Mobetron is a versatile tool for FLASH preclinical research and this comprehensive beam model and workflow was validated to meet the requirements for conducting translational FLASH research.
Analysis in microwave-driven plasma for miniature space propulsion
Authors: Kim Kyungtae , Chai Kil-Byoung , Yun Gunsu S
Published: July 2024

Microwave-driven Coaxial Transmission Line Resonator (µ-CTLR) produces a small-volume high density plasma plume. In the previous study, we discovered that the plasma generated by the µ-CTLR remains stable even at low pressure around tens of mTorr, while consuming minimal power below 10 W (Kim et al 2022 Plasma Sources Sci. Technol.
31 105006). In this study, we have investigated the capability of the µ-CTLR plasma operating at 900 MHz for micro-propulsion applications. At the argon gas flow rate of 100 SCCM (3 mg s−1), and the power of 8 W, the plasma plume attains high gas temperature (

>

3000 K), high electron density (

>

10

20

 

m

−
3

), and electron temperature of about 2 eV. The estimated thrust is about 3.4 mN, demonstrating that the µ-CTLR has high thrust desirable for space micro propulsion systems, together with the other merits of low power consumption and small size.
Topology optimization of smart structures to enhance the performances of vibration control and energy harvesting
Authors: Sena J P , de Lima A M G , Bouhaddi N , Kacem N
Published: July 2024

With the growing interest in smart materials, the utilization of shunted piezoceramics for dynamic vibration control has gained significant attention due to their unique characteristics, such as the ability to absorb strain energy from vibrating systems and convert it into electrical energy. Designing and analyzing the behavior of structures in hybrid mitigation/harvesting conditions, considering both reliability and performance, pose challenges. This paper aims to achieve optimal design parameters for the structure by employing a multiobjective optimization approach that strikes a compromise between maximizing harvested power and minimizing structural damage. To evaluate the effectiveness of the design, topology optimization was conducted in three different cases to compare the results. By systematically exploring the design space, these cases provide insights into the influence of various parameters on the structural performance. In addition, to enhance computational efficiency, the structure was represented as a metamodel using neural networks. This approach enables rapid evaluation and prediction of the structure’s behavior, facilitating the optimization process. By integrating multiobjective optimization, topology optimization, and metamodeling techniques, this study aims to provide valuable insights into the optimal design of structures that simultaneously incorporate shunt circuitry for vibration control and energy harvesting, leading to improved performance and reliability.
Æther coupling effects on casimir energy for self-interacting scalar field within extra dimension
Authors: Valuyan M A
Published: July 2024

This paper presents comprehensive calculations for thermal and first-order radiative corrections to the Casimir energy in systems involving self-interacting massive and massless scalar fields coupled with æther in a fifth compact dimension. The method used to compute the radiative correction to the Casimir energy differs from conventional approaches by applying a unique renormalization scheme that is consistent with specific boundary conditions or backgrounds. Despite this divergence from conventional methodologies, our results demonstrate consistency within established physical limits. Furthermore, employing a toy model, we calculated the total Casimir energy density in the bulk, taking into account both thermal and radiative corrections. We also provide a thorough characterization of the total Casimir energy density in the compact dimension, detailing its magnitude and sign using graphical representations and quantitative data.
Potential for multi-application advancements from doping zirconium (Zr) for improved optical, electrical, and resistive memory properties of zinc oxide (ZnO) thin films
Authors: Chawla Amit K , Hothi Navjot , Umamaheswara Rao Akula , Kharb Archana Singh , Chanana Avaani , Mir Kifayat H , Kumar Pramod , Garg Tarun , Chawla Vipin , Jain Ravish , Pant Charu , Kumar Sanjeev
Published: July 2024

Transition metal-doped Zinc oxide (ZnO) thin films with an optimal wide band gap and semiconducting nature find numerous applications in optoelectronic devices, gas sensors, spintronic devices, and electronics. In this study, Zirconium (Zr) doped ZnO thin films were deposited on ITO (Indium Tin oxide) coated glass substrate using RF-magnetron sputtering. Optical and electrical properties were examined for their potential use in resistive random-access memory (RRAM) applications. X-ray Diffraction (XRD), UV–vis spectroscopy, x-ray photoelectron spectroscopy (XPS), Atomic force microscopy (AFM) and Scanning electron microscopy (SEM) were used to investigate structural, optical, and compositional properties and roughness respectively. The results demonstrate that the films possess crystalline properties. Additionally, an augmentation in Zr concentration correlates with an elevation in the optical band gap, ascending from 3.226 eV to 3.26 eV, accompanied by an increase in Urbach energy from 0.0826 eV to 0.1234 eV. The film with the highest Zr content among all the films demonstrated the best electrical performance for resistive memory applications. Incorporating Zr as a dopant shows enhancement in the electrical performance and such ZnO films with optimum concertation of Zr can potentially be used in RRAM. ZnO being a versatile host material, its doping with Zr may extend its applications in catalysis, gas sensing, energy storage, and biomedical engineering. ZnO thin films employ zirconium (Zr) as a dopant, which is a novel way to improve the material’s characteristics. Although ZnO has been thoroughly researched, adding Zr presents a novel technique to enhance optical, electrical, and resistive memory characteristics all at once that has not been fully investigated.
Privacy-preserving keyword query quantum scheme for outsourced data in cloud environments
Authors: Jia Qianqian , Shi Run-hua , Li Huijie
Published: July 2024

Cloud computing, as a popular technology in recent years, has greatly facilitated the development of data outsourcing services. However, when users access sensitive data stored in the cloud, ensuring the security of data remains a pressing challenge. In this paper, we present a privacy-preserving keyword query scheme for outsourced data in cloud environment. Furthermore, to implement this scheme, we propose a series of quantum basic protocols with single qubits. The proposed basic protocols do not require the execution of quantum gate operations, and the necessary measurements are only Bell measurements based on measurement-device-independence. Therefore, it is practical and feasible under current technology. Moreover, compared with classical schemes, our scheme has higher security (i.e., quantum security). Finally, we conduct simulation experiments in IBM Qiskit to verify the correctness and feasibility of the critical parts of the scheme.
Divergent response of energy exchange to heatwaves from flux tower observations among various vegetation types
Authors: Tian Xiaohui , Qiu Bo , Ni Yueyang , Chen Jiuyi , Li Lingfeng , Cao Yipeng , Zhao Siwen
Published: July 2024

The increasing frequency of European heatwaves and the associated impacts on ecosystems have raised widespread concern during the last two decades. The partitioning of surface energy between latent and sensible heat fluxes plays a pivotal role in regulating heat and water exchange between the land surface and the atmosphere. However, the responses of surface energy partitioning during heatwave events and the contributions of changes in energy partitioning to heatwave development have been underexplored. Here, we investigated the responses of surface energy exchange to temperature extremes during four devastating European heatwaves (2003, 2010, 2018, and 2022) based on long‒term observations from 31 flux towers. Our results demonstrated that the divergent responses of surface energy exchange to heatwaves were modulated by vegetation type and background climate in Europe. Forests maintained similar latent heat fluxes as the climatological mean but largely increased sensible heat under heat‒stressed conditions. While grasslands and croplands tended to increase sensible heat by suppressing latent heat during heatwaves, especially under water‒stressed conditions. Furthermore, the changes in surface energy partitioning strengthened positive land‒atmosphere feedbacks during the heatwave period, leading to unprecedented temperature extremes. This study highlights the importance of surface energy partitioning in land‒atmosphere interactions and heatwave developments.
The EU’s new anti-deforestation law has severe loopholes that could be exploited by the forthcoming EU-MERCOSUR trade agreement
Authors: Fuchs Richard , Raymond Joanna , Winkler Karina , Rounsevell Mark
Published: July 2024

The EU deforestation regulation promises global green leadership, however, loopholes may lead to an increase in the trade of deforestation-implicit agricultural products. Ratification of the EU-MERCOSUR free trade agreement could exploit this situation.
Evaluating effectiveness of clustering algorithms in multiple target stereotactic radiosurgery
Authors: Hui Cheukkai B , Chen Josephine , Pourmoghaddas Amir , Mutaf Ela
Published: July 2024

Objective. Single-isocenter-multiple-target technique for stereotactic radiosurgery (SRS) can reduce treatment duration but risks compromised dose coverage due to potential rotational errors. Clustering targets into two groups can reduce isocenter-target distances, mitigating the impact of rotational uncertainty. However, a comprehensive evaluation of clustering algorithms for SRS is absent. This study addresses this gap by introducing the SRS Target Clustering Framework (Framework), a comprehensive tool that utilizes commonly used clustering algorithms to generate efficient cluster configurations. Approach. The Framework incorporates four distinct optimization objectives based on two key metrics: the isocenter-target distance and the ratio of this distance to the target radius. Agglomerative and weighted agglomerative clustering are employed for minimax and weighted minimax objectives, respectively. K-means and weighted k-means are utilized for sum-of-squares and weighted sum-of-squares objectives. We applied the Framework to 126 SRS plans, comparing results to ground truth solutions obtained through a brute force algorithm. Main results. For the minimax objective, the average maximum isocenter-target distance from agglomerative clustering (4.8 cm) was slightly higher than the ground truth (4.6 cm). Similarly, the weighted agglomerative clustering achieved an average maximum ratio of 15.1 compared to the ground truth of 14.6. Notably, both k-means and weighted k-means clustering showed close agreement (within a precision of 0.1) with the ground truth for average root-mean-square target-isocenter distance and ratio (3.6 cm and 11.1, respectively). Significance. These results demonstrate the Framework’s effectiveness in generating clusters for SRS targets. The proposed approach has the potential to become a valuable tool in SRS treatment planning. Furthermore, this study is the first to investigate clustering algorithms for both minimizing maximum and sum-of-squares uncertainty in SRS.
Engagement Is Personal
Authors: McCourt David
Published: July 2024

This chapter explores a crucial aspect of Engagement’s demise frequently left out of scholarly and popular analysis commentary: the often-intense personal struggles among America’s knowledge communities over policies and frames. Despite decades of expansion and diversification, the U.S. national security community remains a small social space at its upper levels. America’s China watchers typically know many of their colleagues. Key decisions are tied to identifiable individuals. Henry Kissinger is the quintessential example, synonymous with Engagement with China. The rise and fall of Engagement with China, then, was more than an outcome of political and professional contestation. Running orthogonally to both was a personal story of real people’s hopes realized or frustrated, of agendas promoted or blocked as they waged intellectual and bureaucratic battles.
Sect and Superstition: The Protestant Framework of American Codification
Authors: Funk Kellen R
Published: July 2024

Elite lawyers who debated codification in the nineteenth-century United States treated codification as inseparable from a liberal Protestant textualism that had taken hold in the early national era. Legislators declared codification to be the necessary final step of the Protestant Reformation and frequently characterized common law lawyers as beholden to ‘superstition’ and ‘priestcraft’. Their opponents denounced the codifiers’ idea that texts alone could adequately convey common meanings and delighted to point out the endlessly fracturing glosses on supposedly ‘clear’ texts that divided the positivists into an ever-increasing number of sects.

Many works have addressed the relationship between populism and positivism over the course of the codification debates in the United States. What these works have missed is the Protestantism. Understanding how lawyers of another generation approached these questions can help us to appreciate the varieties of American textualism, and the fact that today’s textualism may be as foreign to textualisms of the past as to other methods entirely. Rather than the forerunners of a modern, rationalist ‘Republic of Statutes’, the codifiers were the literal and figurative sons of a post-Calvinist generation that was unquenchably optimistic about the clarity of texts and the common sense of individuals reading them. This lens also helps us better understand the defenders of the common law, who were not so much the retrograde servants of property rights and judicial supremacy as they are often presented, but were more often practically minded lawyers who understood the limits to which legislative texts could change the complex practices of law on the ground.
Associations of Post-Traumatic Stress Disorder and Objective Subtle Cognitive Difficulties in Cognitively Unimpaired Older Veterans
Authors: Garcia Mary Ellen , Rantins Peter , Alshaheri Durazo Alin , Urias Uriel , Weigand Alexandra J , Bangen Katherine J , Bondi Mark W , Jak Amy J , Thomas Kelsey R
Published: July 2024

Introduction

Psychiatric conditions such as post-traumatic stress disorder (PTSD) and depression have a two-fold increased dementia risk in Veterans. Prior work has shown that psychiatric factors can both impact cognitive functioning and be early symptoms associated with Alzheimer’s disease (AD). Objectively defined subtle cognitive difficulties (Obj-SCD) has been associated with cognitive decline and AD biomarkers. However, Obj-SCD has not yet been investigated in the context of psychiatric disorders.

Methods

A total of 179 cognitively unimpaired Veterans (50–92 years old) underwent a comprehensive neuropsychological evaluation at VA San Diego and a retrospective medical record review. Chi-squared tests compared rates of psychiatric diagnoses in Veterans with and without Obj-SCD.

Results

About 21% of the sample was classified as Obj-SCD. Relative to cognitively unimpaired Veterans, Veterans classified as Obj-SCD had higher rates of PTSD, but not higher rates of other psychiatric conditions (e.g., depression). The PTSD findings appear to be driven by measures of cognitive efficiency.

Conclusion

Elevated rates of PTSD, but not other psychiatric conditions, were observed among Veterans with Obj-SCD. The prevalence and type of subtle cognitive difficulties associated with PTSD in older Veterans demonstrates a need, and informs potential targets, for intervention. Further work is needed to determine mechanisms of subtle cognitive difficulties in older Veterans with PTSD.
Introducing field-programmable gate arrays in genotype phasing and imputation
Authors: Wienbrandt Lars , Ellinghaus David
Published: July 2024

We recently developed EagleImp, a free software that combines genotype phasing and imputation in a single tool. By introducing algorithmic and technical improvements we accelerated the classical two-step approach using Eagle2 and PBWT. Here, we demonstrate how to use field-programmable gate arrays (FPGAs) to accelerate EagleImp even further by a factor of up to 93% without loss of phasing and imputation quality. Due to the speed advantage over a not accelerated processor-based implementation, the FPGA extension of EagleImp allows the user to choose a more resource-intensive parameter setting in exchange for computation time to further improve phasing and imputation quality.

Availability and implementation

EagleImp and its FPGA extension are freely available at https://github.com/ikmb/eagleimp and https://github.com/ikmb/eagleimp-fpga.