bluuebunny/crossref_metadata_2025 huggingface dataset:
Indium-catalyzed hydrosilylation of nitroarenes to aromatic amines
Authors: Sai Kumar Gobbilla , Bano Kulsum , Biswal Priyabrata , Dey Soumyadip , Kumar Ravi , Sau Abhijit , Chandrasekhar Vadapalli , Panda Tarun K.
Published: November 2024

Herein, we report the synthesis of three indium complexes (1–3) supported by different chelating ligands (L1–L3).
Human milk metals and metalloids shape infant microbiota
Authors: Flores Ventura Eduard , Bernabeu Manuel , Callejón-Leblic Belén , Cabrera-Rubio Raúl , Yeruva Laxmi , Estañ-Capell Javier , Martínez-Costa Cecilia , García-Barrera Tamara , Collado María Carmen
Published: November 2024

Human milk metals and metalloids are variable and significantly correlate with infant gut microbiota abundance and alpha diversity indices.
Precise weight tuning in quantum dot-based resistive-switching memory for neuromorphic systems
Authors: Kim Gyeongpyo , Yoo Doheon , So Hyojin , Park Seoyoung , Kim Sungjoon , Choi Min-Jae , Kim Sungjun
Published: November 2024

QD-based RRAM is proposed for neuromorphic systems. A HfO2 layer enhances the resistive switching and UV light reduces the switching voltage. MLC with 4 bits achieved can improve ANN performance.
Application of carbon-based nanomaterials in Alzheimer's disease
Authors: Bai Mengyao , Shao Xu , Wang Chao , Wang Juanxia , Wang Xin , Guan Ping , Hu Xiaoling
Published: November 2024

This review elucidates the use of carbon-based nanomaterials of varying dimensions in the diagnosis and therapy of Alzheimer's disease, grounded on several pathogenic theories of AD, while also outlining present problems and future potential.
Particle surface engineering at the nano-micro scale interfaces of metal-nonmetal bonded polymeric coatings: experimental and in silico evaluations
Authors: Yadav Suman , Pandey Sarvesh Kumar , Awasthi Shikha
Published: November 2024

Polyvinyl alcohol (PVA) is a well-known and cost-effective synthetic polymer that offers a variety of applications, including medical, food, aerospace, automotive, and material industries, for the construction of structures.
Conduction band photonic trapping via band gap reversal of brookite quantum dots using controlled graphitization for tuning a multi-exciton photoswitchable high-performance semiconductor
Authors: Sonkaria Sanjiv , Lee Tae Woo , Kumar Aniket , Hwang Soo-Kyung , Jablonski Piotr G. , Khare Varsha
Published: November 2024

Brookite exists as the metastable phase of titania and often mediates the transformation of anatase to rutile.
Recent progress in two-dimensional Bi2O2Se and its heterostructures
Authors: Hu Xiaoyu , He Wen , Wang Dongbo , Chen Lei , Fan Xiangqian , Ling Duoduo , Bi Yanghao , Wu Wei , Ren Shuai , Rong Ping , Zhang Yinze , Han Yajie , Wang Jinzhong
Published: November 2024

Overview of the key aspects of 2D Bi2O2Se and representative schematic diagrams.
Innovations in isocyanate synthesis for a sustainable future
Authors: Vargas Jorge Andrés Mora , Mandrekar Ketan S. , Echemendía Radell , Burtoloso Antonio C. B.
Published: November 2024

Isocyanates play a crucial role in many industries; however, their high reactivity and toxicity have led to an increasing demand for safer, more efficient and selective methods for their synthesis and applications.
Photooxidative C–C double bond cleavage of β-enaminocarbonyl compounds: toward selective N-formylation of amines
Authors: You Hayeon , Lim Suk Hyun , Cho Dae Won
Published: November 2024

A photooxidative C–C double bond cleavage of electron-deficient β-enaminocarbonyl compounds possessing a silyl group at the α-position to the nitrogen atom using methylene blue (MB) as the photosensitizer was explored.
Upconversion nanoparticles incorporated with three-dimensional graphene composites for electrochemical sensing of baicalin from natural plants
Authors: Zhang Na , Wu Yilin , Liang Tian , Su Yongxiang , Xie Xusheng , Zhang Tianren , Wang Hongyan , Zhang Keying , Jiang Rongli
Published: November 2024

The fabrication of UCNP-3DG and its application in electrochemical detection of Bn in natural plant samples.
Polyether-based polyurethane electrolyte for lithium metal battery: a perspective
Authors: Cui Peng , Li Yifan , Liu YuXing , Wang Siqi , Tang Xingyu , Ye Yihong , Su Hance , Sun Chun
Published: November 2024

Mechanism of increasing ionic conductivity of polyether-based polyurethane electrolyte.
A safe and efficient synthesis of N-Boc-β3-amino acid methyl esters from α-amino acids: applications in the formal synthesis of sedum alkaloids
Authors: Long Bohua , Ren Lijie , Jiang Mengmeng , Hu Shengquan , Jiang Qianqian , Li Limin , Chen Xuanluan , Wu Zhengzhi
Published: November 2024

β3-Amino acids are essential components in the synthesis of biologically active compounds.
Ammonia decomposition over low-loading ruthenium catalyst achieved through “adiabatic” plasma reactor
Authors: Shawon Minhazur Rahman , Umeojiakor Chinwendu , Griffin Anthony , Aguinaga Jeffrey , Wu Jiachun , Patton Derek , Qiang Zhe , Toghiani Hossein , Xiang Yizhi
Published: November 2024

The heat effect of nonthermal plasma significantly enhanced the synergy between the plasma and the catalytically active sites. Consequently, nearly 100% NH3 decomposition was achieved over the low-loading Ru/Al2O3 catalyst under adiabatic conditions.
Low temperature decoherence dynamics in molecular spin systems using the Lindblad master equation
Authors: Krogmeier Timothy J. , Schlimgen Anthony W. , Head-Marsden Kade
Published: November 2024

We interface ab initio electronic structure with the Lindblad master equation to predict low temperature decoherence in molecular spins. Relating the electronic structure to the decoherence allows for qualitative agreement with experimental trends.
Simultaneous generation of hydroxyl and hydrogen radicals from H+/OH− pairs caused by water–solid contact electrification
Authors: Chen Fengjie , Wu Jingde , Wang Dou , Xia Yu , Song Qingyuan , Liang Ying , Wang Pu , Chen Bolei , Liang Yong , Yin Yongguang , Wang Yawei , Song Maoyong , Jiang Guibin
Published: November 2024

Water–solid contact electrification is a common physical phenomenon involving interfacial electron and ion transfer, recently discovered to trigger unique redox reactions.
Understanding the formation of nitrate from nitrogen at the interface of gas–water microbubbles
Authors: Bose Sandeep , Xia Yu , Zare Richard N.
Published: November 2024

Water microbubbles containing Fe2+ ions have been found to efficiently transform nitrogen (N2) to nitrate (NO3−) by initiating Fenton's reaction at the gas–water interface.
Surfing the limits of cyanine photocages one step at a time
Authors: Janeková Hana , Fisher Sergey , Šolomek Tomáš , Štacko Peter
Published: November 2024

Near-infrared light-activated photocages enable controlling molecules with tissue penetrating light.
Quantum DFT analysis and molecular docking investigation of various potential breast cancer drugs
Authors: Ayub Md Ashraf , Tyagi Ankit Raj , Srivastava Sunil Kumar , Singh Pranveer
Published: November 2024

DFT and molecular docking studies were used to evaluate selected anticancer drugs to provide insights into the drugs' structural, electronic, and reactivity profiles and their binding to breast cancer targets.
Pressure-induced tunable emission colors and irreversible bandgap narrowing in organic–inorganic manganese bromide hybrids
Authors: Fu Ruijing , Gao Junpeng , Zhang Pinsen , Wang Lingrui , Wang Bo , Wang Guangxia , Li Xiaoshuang , Kong Youchao , Zeng Qingguang , Xiao Guanjun
Published: November 2024

The zero-dimensional (C24H20P)2MnBr4 exhibits remarkable high-pressure-induced emission tuning that shifts from green to red and an irreversible bandgap narrowing of 1.09 eV.
Implementing Transparency in Learning and Teaching in Higher Ed in Speech Science Coursework: A Tutorial
Authors: Mandulak Kerry Callahan
Published: November 2024

Purpose:

Transparent Instruction in Learning and Teaching in Higher Ed (TILT Higher Ed) is an evidence-based teaching method that can be used in Speech Science teaching to facilitate success of all learners. In addition, TILT Higher Ed has been found to provide an inclusive learning environment and promote belonging in the classroom context.

Conclusions:

The goal of this tutorial is to provide background information, a rationale, and a guide for implementation of the core principles of TILT Higher Ed into Speech Science coursework, which includes Transparent Assessment Design and Transparent Teaching Methods. A case will also be made for an overall shift of increased use of inclusive teaching methods within undergraduate communication sciences and disorders courses.
Delay management for heterogeneous traffic in vehicular sensor networks using packet fragmentation of low priority data
Authors: Khan Anwar Ahmed , Siddiqui Shama , Siddiqui Muhammad Shoaib
Published: November 2024

Vehicular sensor networks (VSNs) are expected to revolutionize the transportation systems through automated decision‐making. These networks function on the communication between vehicles, traffic infrastructure, and people. One of the major challenges of VSNs is to deal with heterogeneous traffic due to the diverse nature of information and data generated by different types of sensors and devices within the vehicular environment. To ensure an effective operation of the network, it is crucial to offer a differentiated quality of service to each traffic class. Media access control (MAC) protocols offer an opportunity to provide differentiated channel access to the traffic of different priorities. This work is focused on offering comparison of recent MAC schemes in terms of their performance for heterogeneous traffic generated by VSNs. Two protocols FROG‐MAC and UrgMAC have been selected: FROG‐MAC is developed using a simple concept of packet fragmentation, where the packets of lower priority are fragmented to offer an early transmission opportunity to urgent traffic; on the other hand, urgMAC is designed using advanced cross‐layer techniques of two‐tiered service differentiation mechanism, adaptive data rate adjustment mechanism, urgency‐based contention window size adaptation, traffic type adaptive duty cycle, and multimedia message passing. It has been found that the FROG‐MAC outperforms urgMAC in terms of delay, energy consumption and packet delivery ratio.
Catalytic oxidation of CO over CuO@TiO2 catalyst: The relationship between activity and adsorption performance
Authors: Bai Yuan , Shi Ping , Zhang Xin , Wei Fei , Chen Liguo , Song Jing , Qiu Jian , Chen Bin , Zhu Hong , Xu Haitao
Published: November 2024

The emission of CO toxic gases seriously endangers environmental safety and human health. At present, the use of catalysts for catalytic oxidation of CO has become the mainstream research direction. In this study, CuO@TiO2 catalysts with different ratios were prepared by solvent hydrothermal method, and the effects of reaction pretreatment temperature and other factors on the catalytic oxidation performance of CO were investigated. The experimental results show that the catalyst can achieve 100% conversion of CO at 115°C under the condition of pretreament at 350°C for 2 h. This excellent performance is due to the uniform distribution of the active component on the surface of the TiO2 support, and the large pore structure constructed by the solvent hydrothermal method enhances the adsorption and activation of CO. This work provides an idea for the preparation of CO oxidation catalysts.
Integrated energy microgrids participating in voltage regulation ancillary services: An improved ADMM based distributed optimization approach
Authors: Xiao Hao , Pei Wei , Han Daoxin , Pu Xiaowei , Wang Jiarui
Published: November 2024

The integrated energy microgrid (IEM) has good potential for both active and reactive power regulation, which are gradually becoming critical resources for participating in power system ancillary services. This paper constructs a distributed optimization model for the IEMs participating in voltage regulation ancillary services by considering multiple physical network constraints. To reduce computational complexity, the DistFlow power flow model and the second‐order cone relaxation method are introduced to transform the optimization model into a second‐order cone programming problem. Moreover, an improved accelerated consensus alternating direction method of multipliers algorithm is proposed to accelerate distributed optimization solutions of the model while protecting user privacy. Finally, the proposed optimization model and solution method are tested in the modified IEEE‐33 node test case to verify their effectiveness and feasibility.
Efficacy of anti-obesity medication (AOM) and endoscopic gastric remodeling (EGR): Analysis of combination therapy with optimal timing and agents
Authors: Jirapinyo Pichamol , Jaroenlapnopparat Aunchalee , Thompson Christopher C.
Published: November 2024

Background and study aims Endoscopic gastric remodeling (EGR) and anti-obesity medications (AOMs) are effective weight loss therapies. While the efficacy of EGR and AOMs has been established, the effect of combination therapy and its optimal approach remain unknown.

Patients and methods This was a single-center retrospective
review of prospectively collected data from patients who underwent EGR. Patients were
categorized as: 1) monotherapy – EGR alone; 2) combination therapy – an AOM prescribed within
6 months of EGR; and 3) sequential therapy – an AOM prescribed greater than 6 months of EGR.
Outcomes included percent total weight loss (%TWL) at 12 months, response rate (≥ 10%TWL at 12
months), and serious adverse event rate.

Results A total of 208 patients were included. Of them, 65 (34%), 61 (31%), and 82 (35%) underwent monotherapy, combination therapy, and sequential therapy, respectively. At 12 months, patients who received EGR+GLP-1RA combination therapy achieved the greatest weight loss (23.7±4.6% TWL), while those who began with AOM followed by EGR more than 6 months later had the lowest weight loss (12.0±7.7%TWL) compared with monotherapy (17.3±10.0% TWL) (P = 0.04 and 0.03, respectively). The response rate was 100% for EGR+GLP-1RA combination therapy and 56% for AOM followed by EGR sequential therapy (P = 0.02).

Conclusions Combining AOM with EGR appears to result in greater weight loss compared with other strategies, with GLP-1RA as the preferred agent and optimal initiation of both therapies occurring within 6 months of each other. Prolonged medication use prior to EGR appears to be associated with suboptimal weight loss, suggesting the importance of early referral for adjunctive therapy.
Advancements in MELD Score and Its Impact on Hepatology
Authors: Hudson David , Valentin Cortez Francisco Javier , León Ivonne Hurtado Díaz de , Malhi Gurpreet , Rivas Angelica , Afzaal Tamoor , Rad Mahsa Rahmany , Diaz Luis Antonio , Khan Mohammad Qasim , Arab Juan Pablo
Published: November 2024

There continues to be an ongoing need for fair and equitable organ allocation. The Model for End-Stage Liver Disease (MELD) score has evolved as a calculated framework to evaluate and allocate patients for liver transplantation objectively. The original MELD score has undergone multiple modifications as it is continuously scrutinized for its accuracy in objectively representing the clinical context of patients with liver disease. Several refinements and iterations of the score have been developed, including the widely accepted MELD-Na score. In addition, the most recent updated iteration, MELD 3.0, has been created. The MELD 3.0 calculator incorporates new variables such as patient sex and serum albumin levels and assigns new weights for serum sodium, bilirubin, international normalized ratio, and creatinine levels. It is anticipated that the use of MELD 3.0 scores will reduce overall waitlist mortality and enhance access for female liver transplant candidates. However, despite the emergence of the MELD score as one of the most objective measures for fair organ allocation, various countries and healthcare systems employ alternative methods for stratification and organ allocation. This review article will highlight the origins of the MELD score, its iterations, the current MELD 3.0, and future directions for managing liver transplantation organ allocation.

Lay Summary

Organ donation is crucial for the management of patients unwell with liver disease, but organs must be allocated fairly and equitably. One method used for this is the Model for End-Stage Liver Disease (MELD) score, which helps objectively decide which patient is a candidate for liver transplant. Over time, the MELD score has been refined to better reflect patients' needs. For example, the latest version, MELD 3.0, now considers factors like nutrition and gender. This should ensure that more patients, especially females, are candidates and receive appropriate access to liver transplantation. However, not every country uses the MELD score. Some countries have created their own scoring systems based on local research. This review will explain where the MELD score came from, how it has changed, the current characteristics of the MELD 3.0 score, and what the future might hold for organ allocation in liver transplants.
CBCT Guidance for Removing Foreign Object from the Jawbone: A Case Study
Authors: Rizqiawan Andra , Kamadjaja David B. , Raka Dewa Gede , Nisa Kharisma , Ramadhani Nastiti Faradilla , Nurrachman Aga Satria
Published: November 2024

Foreign objects lodged in the mandibular bone often result from trauma or dental procedures. Accurate localization of these foreign objects is crucial for guided surgical removal, especially when patients present with persistent pain. Conventional imaging modalities like periapical and panoramic radiographs may not provide sufficient detail for precise localization. Cone beam computed tomography (CBCT) has emerged as a valuable tool for guided surgical interventions owing to its superior imaging capabilities. We present two cases of foreign objects lodged in the mandible, where patients complained of prolonged pain, soreness, and numbness in the right mandible extending to the head and behind the ear. Both patients had undergone previous right mandibular tooth extractions and received treatment from a neurologist without resolution of symptoms. Both cases showed the control improvement in complaints, and no paresthesia or postoperative complications were found. CBCT-guided surgical removal was performed in both cases, revealing a metal specimen measuring 6 × 3 × 1 mm3 in the first patient and a remaining root measuring 5 × 3 × 2 mm3 in the second patient. Diagnosing foreign objects in the mandible poses challenges due to their varied size, composition, and proximity to vital structures. CBCT offers superior imaging resolution, enabling precise localization and assessment of anatomical relationships, such as the distance to the inferior alveolar nerve and surrounding boundaries. CBCT emerges as the preferred imaging modality for diagnosing and guiding the surgical removal of foreign objects in the mandible. Its advantages include accurate localization, low radiation exposure, and cost-effectiveness. Compared with CT scans, CBCT also offers faster scanning times, making it a valuable tool in clinical practice for managing such cases
Remineralizing Potential of Natural Hydroxyapatite from Snakehead (Channa striata) Fish Bone on Remineralization of Primary Teeth Enamel: An In Vitro Study
Authors: Dewi Nurdiana , Rahmah Rindha Aulia , Wardhana Agung Satria , Puspitasari Dewi , Wasiaturrahmah Yusrinie , Gustiono Dwi
Published: November 2024

Objective This study aimed to investigate the effect of hydroxyapatite from snakehead (Channa striata) fish bone on the surface hardness of the enamel of the primary teeth.

Materials and Methods Twenty-six primary maxillary incisors were mounted on self-cured acrylic resin, divided into two groups, and demineralized. Remineralization was performed using hydroxyapatite paste synthesized from C. striata fish bone by the precipitation method. The case group was subjected to 15% hydroxyapatite paste and subsequently submerged in artificial saliva, while the control group was only exposed to artificial saliva. Enamel hardness was measured by the Vickers hardness tester after 7 days of treatment. The statistical analysis used in this research was an independent t-test.

Results The case group had a surface hardness of 356.192 ± 25.218, and the control group had a surface hardness of 269.686 ± 22.931. Statistical tests showed a significant difference between the case and control groups.

Conclusion Hydroxyapatite paste from snakehead (C. striata) fishbone stimulates remineralization of primary teeth, as evidenced by an increase in the enamel surface hardness of the teeth.
Correction of Severe Pterygium Colli with a Staged, Double, Posterior and Lateral Approach: A Case Report
Authors: San Basilio María , Lorca-García Concepción , de la Torre Manuel , Terrados Rocío , Berenguer Beatriz
Published: November 2024

Pterygium colli is a rare congenital disorder characterized by excessive skin in the lateral and posterior neck, often associated with genetic syndromes such as Turner's syndrome or Klippel–Feil syndrome. Severe presentations present special challenges for surgeons since its diagnosis is not always evident and its treatment often results in important scaring. Surgical correction of the typical cases mostly involves a lateral approach, but in this “special” case, we used a double, posterior and lateral approach. A 15-month-old girl with prenatal diagnosis of a cystic lesion in the posterior neck presented with massive neck webbing at birth. Genetic studies ruled out chromosomal disorders and RASA 1 mutations. Surgical correction involved a modified posterior approach combined with a lateral approach 1 year later. The cervical tissue redundancy was successfully reduced achieving a good aesthetic outcome with very acceptable scars. At 1 year of follow-up, the patient continues with good neck appearance and mobility. The goal of surgical treatment of pterygium colli is achieving a harmonious neck contour with good function and minimal scarring while minimizing complications and sequelae. No consensus exists on the optimal approach for its correction, emphasizing the need for individualized treatment considering patient-specific characteristics, particularly in the severe cases.
Giant Cell Tumor of Capitate with Secondary Aneurysmal Bone Cyst: A Case Report
Authors: Ramanujapuram Suneel , Parameswaran Apurve , Perubhotla Lakshmi Manasa , Mohammed Murtuza Ahmed , Shah Harshil Nitinkumar , Eachempati Krishna Kiran
Published: November 2024

Background Giant cell tumors (GCTs) of the carpal bones are rare. GCTs of the hand tend to be aggressive, could result in multifocal presentation, and have a high rate of recurrence.

Case Description We report a rare case of GCT of the capitate with secondary aneurysmal bone cyst (ABC) in a 40-year-old man. The patient presented with complaints of pain and swelling over his right wrist since 6 months. Radiographs showed the presence of a lytic lesion in the capitate. Magnetic resonance imaging scanning revealed a well-defined, lobulated, multiseptate lytic lesion involving the entire capitate, extending into its subarticular regions. Fine-needle aspiration revealed findings suggestive of a GCT. He underwent en-bloc excision of the capitate, bone grafting of the defect using an appropriately sized bicortical iliac crest autograft, and third carpometacarpal and midcarpal fusion. Histopathological examination of the lesion confirmed the presence of a GCT, with a secondary ABC. At 3 years following surgery, he was asymptomatic with no signs of tumor recurrence, radiocarpal arthritis, or instability. He was able to perform 45 and 60 degrees of wrist extension and flexion, respectively.

Literature Review To our knowledge, there are no prior reported cases of GCT of the capitate with a secondary ABC.

Clinical Relevance GCTs of the hand in general have a high rate of recurrence. The presence of a super-added ABC could further increase this risk. In the authors' opinion, en-bloc excision of the affected bone, reconstruction of the defect, and appropriate fusion is the optimal mode of management of these cases.
“To the crematorium”: postwar U.S. tourism to West German concentration camps and beyond
Authors: Werle Leonie
Published: November 2024

For a long time since the end of the Second World War, the memory of concentration camps influenced U.S. public views on Germany. When in the late 1940s Americans could travel to West Germany again, a new tourist industry brought West Germany, and with-it Germany’s recent past, closer to the U.S. American public. This article investigates the renewed travel interest of Americans in West Germany with a special focus on former concentration camp sites. It demonstrates the importance of tourism in creating new cultural ties, the ways in which U.S. tourism to the camps established a memory of the Second World War, and how these narratives influenced German-American relations. In newspaper articles, visitors to West Germany shared their experiences, attitudes, and challenges upon visiting the former concentration camp sites and through those interactions made sense of the war and their own position in the postwar world order.
Thermodynamic limit for the magnetic uniform electron gas and representability of density-current pairs
Authors: Csirik Mihály A. , Laestadius Andre , Tellgren Erik I.
Published: November 2024

Although the concept of the uniform electron gas is essential to quantum physics, it has only been defined recently in a rigorous manner by Lewin, Lieb and Seiringer. We extend their approach to include the magnetic case, by which we mean that the vorticity of the gas is also held constant. Our definition involves the grand-canonical version of the universal functional introduced by Vignale and Rasolt in the context of current-density-functional theory. Besides establishing the existence of the thermodynamic limit, we derive an estimate on the kinetic energy functional that also gives a convenient answer to the (mixed) current-density representability problem.
180 mW, 1 MHz, 15 fs carrier-envelope phase-stable pulse generation via polarization-optimized down-conversion from gas-filled hollow-core fiber
Authors: Srivastava Anchit , Scheffter Kilian , Jun Soyeon , Herbst Andreas , Fattahi Hanieh
Published: November 2024

Gas-filled hollow core fibers allow the generation of single-cycle pulses at megahertz repetition rates. When coupled with difference frequency generation, they can be an ideal driver for generating carrier-envelope phase stable, octave-spanning pulses in the short-wavelength infrared. In this work, we investigate the dependence of the polarization state in gas-filled hollow-core fibers (HCF) on the subsequent difference frequency generation stage. We show that by adjusting the input polarization state of light in geometrically symmetric systems, such as hollow-core fibers, one can achieve precise control over the polarization state of the output pulses. This manipulation preserves the temporal characteristics of the generated ultrashort pulses, especially when operating at a near single-cycle regime. We leverage this property to boost the downconversion efficiency of the near single-cycle pulses in a type I difference frequency generation stage. Our technique overcomes the bandwidth and dispersion constraints of the previous methods that rely on broadband waveplates or adjustment of crystal axes relative to the laboratory frame. This advancement is crucial for experiments demanding pure polarization states in the eigenmodes of the laboratory frame.
Polarity controlled ScAlN multi-layer transduction structures grown by molecular beam epitaxy
Authors: Mondal Shubham , Hershkovitz Eitan , Baucom Garrett , Hasan Tanim Md Mehedi , Dabas Shaurya , Chatterjee Baibhab , Kim Honggyu , Tabrizian Roozbeh , Mi Zetian
Published: November 2024

We report on the molecular beam epitaxial growth and characterization of polarity-controlled single and multi-layer Scandium Aluminum Nitride (ScAlN) transduction structures grown directly on ScAlN templates deposited by physical vapor deposition (PVD) on Si(001) substrates. It is observed that direct epitaxial growth on PVD N-polar ScAlN leads to the flipping of polarity, resulting in metal (M)-polar ScAlN. By effectively removing the surface impurities, e.g., oxides, utilizing an in situ gallium (Ga)-assisted flushing technique, we show that high quality N-polar ScAlN epilayers can be achieved on PVD N-polar ScAlN templates. The polarity of ScAlN is confirmed by utilizing polarity-sensitive wet chemical etching and atomic-resolution scanning transmission electron microscopy. Through interface engineering, i.e., the controlled formation or removal of surface oxides, we have further demonstrated the ability to epitaxially grow an alternating tri-layer piezoelectric structure, consisting of N-polar, M-polar, and N-polar ScAlN layers. Such multi-layer, polarity-controlled ScAlN structures promise a manufacturable platform for the design and development of a broad range of acoustic and photonic devices.
Constructing surface oxygen vacancy in the [Bi2O2]2+ layer defects mediated Bi2MoO6 enhanced visible light responsive photocatalytic activity
Authors: Zhu Yali , Wu Rong , Li Aolin , Hui Jialei , Zhang Zhilong , Wei Shunhang
Published: November 2024

Bi2MoO6 nanospheres with surface oxygen vacancies (SOVs) controlled by the calcination process were prepared in this study. Performance testing revealed that the Bi2MoO6-4 sample (Bi2MoO6 calcined at 350 °C for 4 h) with SOVs achieved a remarkable photocatalytic degradation efficiency up to 99.16% for Rhodamine B (RhB) within 50 min, which is 2.19 times higher than that of pure Bi2MoO6. The higher photocatalytic performance of the Bi2MoO6-4 sample is attributed to the SOVs’ defect level located at the Bi2MoO6 bandgap, narrowing the bandgap to effectively promote the photogenerated charge separation. The promotion of photocarrier separation and electron were transferred due to the Bi–O bond breakage in the Bi2MoO6-4 [Bi2O2]2+ layer, which mediates the defect level of SOVs in the band structure. The density functional theory calculation results reveal the possible formation site of the oxygen vacancy and the vacancy-induced defect states. This study provides a new approach for fabricating new photocatalysts with surface oxygen defects.
Comparative study of turbulent round jet flows through direct numerical simulation at medium–high Reynolds numbers
Authors: Nguyen Cat Tuong , Oberlack Martin
Published: November 2024

This study examines a spatially evolving turbulent round jet at a Reynolds number of Re = 7000 based on the bulk velocity Ub and the orifice diameter D and a Prandtl number of Pr = 0.71 using direct numerical simulation (DNS). Statistical data are collected over 30 000D/Ub time units, including mean quantities, Reynolds stresses, heat fluxes, mixed moments, Reynolds stress and turbulent kinetic energy budgets, and probability density functions. Comparative analysis with a previous DNS at Re = 3500 (Nguyen and Oberlack, 2024a; 2024c) shows that the higher Reynolds number leads to a shift of the self-similarity to a greater distance from the orifice. A larger Reynolds number leads to higher magnitudes of different statistical moments, dissipation and production. In addition, a maximum visible in the near-field of the turbulence intensity components is smoothed at the larger Reynolds number. The probability density functions of the axial velocity and the passive scalar show Gaussian behavior on the centerline, but with larger standard deviations compared to the lower Reynolds number. The study highlights the significant impact of using a fully developed turbulent pipe flow profile as the inlet condition, which significantly reduces the size of the potential core by introducing initial turbulence intensities at the orifice.
Simplification of solvation shell with water clusters in the simulation of electrochemical nitrogen reduction reaction
Authors: Liu Han-Xuan , Huang Zheng-Qing , Gao Xin , Yang Guidong , Chang Chun-Ran
Published: November 2024

Electrochemical methods for nitrogen reduction have received extensive attention due to the mild reaction conditions. In order to gain an insight into the mechanism of the electrochemical nitrogen reduction process, theoretical simulations are necessary. However, current simulation studies contain many imprecise approximations that may hinder the real recognition of the reaction process. Although solvation methods have recently been developed to provide efficient descriptions, their further applications are hindered by controversy over modeling of solvents and the enormous computational effort required. In this work, we simplify the solvation conditions by using water clusters and compare them with an accurate water layer model. The results demonstrate that the simplified water clusters can effectively capture protons, simulate the surface electric environment, and enable the calculation of the activation energy of the reaction. This method offers an affordable approach for simulating the surface potentials and solvents and provides a new reference for the theoretical study of the electrochemical nitrogen reduction reaction.
Pursuing high-fidelity control of spin qubits in natural Si/SiGe quantum dot
Authors: Wang Ning , Wang Shao-Min , Zhang Run-Ze , Kang Jia-Min , Lu Wen-Long , Li Hai-Ou , Cao Gang , Wang Bao-Chuan , Guo Guo-Ping
Published: November 2024

Electron spins in silicon quantum dots are a promising platform for fault-tolerant quantum computing. Low-frequency noise, including nuclear spin fluctuations and charge noise, is a primary factor limiting gate fidelities. Suppressing this noise is crucial for high-fidelity qubit operations. Here, we report on a two-qubit quantum device in natural silicon with universal qubit control, designed to investigate the upper limits of gate fidelities in a non-purified Si/SiGe quantum dot device. By employing advanced device structures, qubit manipulation techniques, and optimization methods, we have achieved single-qubit gate fidelities exceeding 99% and a two-qubit controlled-Z (CZ) gate fidelity of 91%. Decoupled CZ gates are used to prepare Bell states with an average fidelity of 91%, typically exceeding previously reported values in natural silicon devices. These results underscore that even natural silicon has the potential to achieve high-fidelity gate operations, particularly with further optimization methods to suppress low-frequency noise.
Local structural disorder introduced by Cr in fcc high-/medium-entropy alloys consisting of 3d transition metal elements
Authors: Furuya D. , Oda M. , Chen Z. , Li L. , Murakawa H. , Sakai H. , Nitani H. , Niwa Y. , Abe H. , Uetsuka H. , Karube T. , Inui H. , Hanasaki N.
Published: November 2024

High-/medium-entropy alloys (H/MEAs) have attracted attention for their excellent mechanical properties. According to first-principles calculations, the atomic displacements from their lattice points are element-dependent and correlated with the yield strength of H/MEAs. To investigate experimentally the element dependence of the local structure, we measured the extended x-ray absorption fine structure in seven kinds of face-centered cubic H/MEAs consisting of 3d transition metal elements. Our experimental results indicate that the local disorder around chromium (Cr) is larger than that around other elements, which is a common feature in all the measured fcc H/MEAs, aligning with prior theoretical studies indicating larger displacements of Cr in comparison to other elements. We discuss the mechanism underlying the local structural disorder induced by the constituent element Cr.
Acoustic sub-wavelength imaging via a virtual super-lens
Authors: Zheng Chen , Zeng Long-Sheng , Li Zong-Lin , Lin Zi-Bin , Wu Peng , Liu Tuo , Peng Yu-Gui , Zhu Xue-Feng
Published: November 2024

Overcoming the diffraction limit has been a long-lasting pursuit for researchers owing to the great potential it offers in going beyond the fundamental resolution restriction in imaging processes. In acoustics, meta-lenses have been a promising way to achieve sub-wavelength imaging, the practical application of which, however, has been limited by expensive material manufacturing, complex system setup, and material loss. Here, we propose a set of procedures equivalent to a virtual super-lens that selectively amplifies the evanescent wave components in the measured acoustic field spectrum, thereby enabling super-resolution imaging without any auxiliary setups or purposely designed super-lens. The proposed virtual super-lens is experimentally verified by considering the imaging of an irregularly shaped sample with sub-wavelength features. We further demonstrate the robustness of the high-quality imaging performance remains acceptable with some environment background noises. In the light of the simple experimental setup involved, our proposed method is flexible and can be readily applied to various practical imaging scenarios.
Jets in cross-flow as wind barrier: Best performing cases and protection mechanism
Authors: Franco I. , Cataldo J. , Gutiérrez A.
Published: November 2024

The use of multiple jets in a cross-flow as wind barriers was proven in a previous study [Franco et al. (2022)]. This study continues the analysis by expanding the wind tunnel tests on twin jets in cross-flow configurations, providing a more detailed description of the leeward flow field of the jets and explaining the mechanism responsible for the good performance of the wind barrier. Hot-wire anemometer measurements were performed on a 324-node grid for 24 combinations of velocity ratios and distances between the jets. This study focuses on two cases characterized by their good performance as wind barriers.
Simulating the Landau–Zener sweep in deeply sub-Ohmic environments
Authors: Kahlert Felix , Link Valentin , Hartmann Richard , Strunz Walter T.
Published: November 2024

With the goal to study dissipative Landau–Zener (LZ) sweeps in realistic solid-state qubits, we utilize novel methods from non-Markovian open quantum system dynamics that enable reliable long-time simulations for sub-Ohmic environments. In particular, we combine a novel representation of the dynamical propagator, the uniform time evolving matrix product operator method, with a stochastic realization of finite temperature fluctuations. The latter greatly reduces the computational cost for the matrix product operator approach, enabling convergence in the experimentally relevant deeply sub-Ohmic regime. Our method allows the exact simulation of dynamical protocols with long operation times, such as the LZ sweep, in challenging parameter regimes that are realized in current experimental platforms.
Rational design of MoS2/CNT heterostructure with rich S-vacancy for enhanced HER performance
Authors: Sun Yuxin , Li Jinhua , Wang Zhiying , Tan Fengxue , Shi Kaixi , Zhai Yingjiao
Published: November 2024

Molybdenum disulfide (MoS2) is a promising electrocatalyst for the hydrogen evolution reaction (HER) due to excellent stability and low cost. However, the utilization in electrocatalytic hydrogen evolution is constrained by inherent shortcomings, including fewer edge active sites, poor dispersion, and electrical conductivity. In this work, MoS2 was compounded with carbon nanotubes (CNTs), which are known for their high specific surface area and excellent electrical conductivity. These CNTs, laden with oxygen-containing functional groups, provided nucleation sites that facilitated the rapid assembly of MoS2 nanoflowers under hydrothermal conditions within 3 h. Due to their diminutive size (∼300 nm), these nanoflowers possess a large specific surface area and numerous active sites at their edges. Furthermore, MoS2 nanoflowers exhibited a high concentration of intrinsic S-vacancies. This heterojunction material exhibited superior HER properties. In addition, density functional theory simulation further confirmed that the MoS2 with S vacancy and CNT heterojunction electrocatalysts (VS-M/C) provided a fast charge transfer pathway for water electrolysis, and analysis showed that the conduction band minimum and valence band maximum were mainly contributed by the d orbits of Mo and the p orbits of C. This study proffered a novel approach for the engineering of high-performance MoS2-based HER electrocatalysts.
Interplay of c- and a-domains on the anomalous electrocaloric effect in BaTiO3 (001) single crystals
Authors: Chatterjee Subhashree , Yadav Kusampal , Barman Shubhankar , Hasina Dilruba , Mukherjee Devajyoti
Published: November 2024

Electrocaloric effects of adiabatic temperature change via the application of external electric fields are explored for energy-efficient solid-state refrigeration. These effects are typically estimated from the thermodynamic analyses of polarization and field in electrocaloric materials, which implies that higher field application gives larger temperature changes. However, this may not be always true. Here, using both indirect and direct methods, we report an anomalous effect where larger thermal changes occur by applications of lower fields in a multi-domain BaTiO3 (001) single crystal. A large temperature change of 1.9 K under a low field change of 8 kV/cm at 404 K is observed in a multi-domain BaTiO3 (001) single crystal in comparison to that of 1.4 K at a high field change of 30 kV/cm. We attribute this counterintuitive effect to the interplay of the c- and a-domains in the BaTiO3 (001) single crystal under the influence of temperature and field changes. This work provides a fundamental understanding of the complex role of domains in governing the electrocaloric response of ferroelectric materials which is often overlooked but critical for their practical applications.
Existence condition for detonations in condensed explosives with pressure–temperature equilibrium models
Authors: Chiapolino Alexandre , Saurel Richard , Bodard Sébastien
Published: November 2024

Most engineering tools dealing with detonation waves in condensed explosives are based on the reactive Euler equations, which involve a thermodynamic closure based on temperature and pressure equilibrium conditions. Indeed, the reactant and the detonation products are assumed to evolve in mechanical and thermal equilibrium. Although the assumption of thermal equilibrium is physically questionable, the reactive Euler equations are used for convenience. This choice is supported by several reasons. When considering thermal equilibrium, the assessment of thermal exchanges between the reactant and the detonation products is simplified, as no exchange coefficient needs to be determined. Furthermore, the reactive Euler equations are in conservative form and the shock relations are well-defined. This model appears to be the simplest option for addressing detonations in condensed explosives. However, this simplicity has limitations and conceals a subtle difficulty that can lead to pathological detonations. The present contribution investigates this difficulty and presents a global exothermic condition to preserve exothermic detonations in the frame of temperature–pressure equilibrium flow models. This condition depends on the equations of state only. It is independent of the kinetics used to model the decomposition of the explosive. By meticulously selecting the thermodynamic parameters of the equations of state for the reactant and detonation products, pathological detonations are prevented, thereby maintaining a globally exothermic reaction consistent with the Zeldovich–von Neumann–Döring theory.
Isolator shape transition impact on hypersonic internal waverider intake flow distortion
Authors: Musa Omer , Huang Guoping , Adam Abdalazeem , Yu Zonghan
Published: November 2024

This paper examines the impact of scramjet isolator shape transition on hypersonic internal waverider (IWR) intake. The IWR intake is designed using the osculating axisymmetric flows and streamline-tracing methods. The new Internal Conical Flow “M” basic flowfield is utilized to provide the flow information for the design method. The intake is equipped with three isolators: one with a constant cross section and two with variable cross sections with circular and rectangular exits. The entrance shape and area of the three isolators are fixed to the intake throat shape and area. The exit area of the three isolators is maintained as the entrance one. Numerical computations of three-dimensional configurations reveal that the isolators with variable cross section shapes demonstrate a higher uniformity index than those with constant cross section shape. Thus, the isolator shape transition has decreased the flow distortion of the hypersonic IWR intake system. The three isolators exhibit varied wall pressure distribution depending on the isolator cross section shape, and the total pressure recovery ratios at the three isolators' exit planes are similar. The wall pressure distributions and key performance parameters at the intake throat section, including total pressure recovery, compression ratio, and Mach number, remained consistent across the first part of the intakes. Therefore, changing the cross section shape of the isolator while keeping the area constant could enhance the flow uniformity of compressed air without negatively impacting the intake system's performance. This allows a separate shape selection of the IWR intake throat and the scramjet combustor entrance to fulfill their special requirements.
Multi-directional and multi-modal vortex-induced vibrations for wind energy harvesting
Authors: Xia Cuipeng , Tang Lihua , Yin Peilun , Aw Kean C.
Published: November 2024

A conventional vortex-induced vibration (VIV)-based energy harvester is typically restricted to capturing wind energy from a very limited range of wind directions, making it inefficient in varying wind conditions. This Letter proposes a tri-section beam configuration for VIV-based piezoelectric energy harvester to enable harnessing wind energy from varying incident angle with different vibration modes being triggered. The finite element analysis investigates the tri-section beam harvester's mode shapes and natural frequencies. A wind tunnel experiment is conducted for a comparative study of the energy output performance of the harvesters with straight and tri-section beams. The findings show that the proposed harvester with the tri-section beam can efficiently capture wind energy from a much wider range of incident angles, as opposed to the specific limited directions of its counterpart with the straight beam. The proposed harvester can also widen the lock-in speed range with a higher bending mode being triggered and achieve the optimal output power of 1.388 mW when the proposed harvester works in the second mode at a higher natural frequency, superior to that of its counterpart (0.386 mW) that can only work in the first mode. The proposed configuration sheds light on developing multi-directional and multi-modal VIV-based energy harvesters adapted to wind conditions in natural environments.