Publications by authors named "Hongqi Xu"

Objectives: Brain-behavior connections are a new means to evaluate sports performance. This electroencephalogram (EEG) study aims to estimate endurance exercise performance by investigating eigenvalue trends and comparing their sensitivity and linearity.

Methods: Twenty-three cross-country skiers completed endurance cycling tasks.

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We report an experimental study of a 1D quintuple-quantum-dot array integrated with two charge sensors in an InAs nanowire. The device is studied by measuring double quantum dots formed consecutively in the array, and corresponding charge stability diagrams are revealed with both direct current measurements and charge sensor signals. The one-dimensional quintuple-quantum-dot array is then tuned up, and its charge configurations are fully mapped out with the two charge sensors.

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This study aimed to utilize the nonnegative matrix factorization (NNMF) algorithm for muscle synergy analysis, extracting synergy structures and muscle weightings and mining biomarkers reflecting changes in muscle fatigue from these synergy structures. A leg press exercise to induce fatigue was performed by 11 participants. Surface electromyography (sEMG) data from seven muscles, electrocardiography (ECG) data, Borg CR-10 scale scores, and the z-axis acceleration of the weight block were simultaneously collected.

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Objective: To tackle non-specific low back pain (NSLBP) among patients and find the most effective solution and to quantitatively synthesize the overall effect of motor control training (MCT) compared with Pilates, McKenzie method, and physical therapy (PT) in pain and physical function.

Methods: Randomized controlled trials (RCTs) of four types of intervention (MCT, Pilates, McKenzie method, and PT) for LBP were collected by searching PubMed, Web of Science, EBSCOhost (Cochrane Central Register of Controlled Trials), and Scopus databases from the establishment of the database to September 30, 2023. The risk of bias was evaluated for included studies using the Revised Cochrane Risk of Bias tool for randomized trials (RoB 2.

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We report an experimental study of proximity induced superconductivity in planar Josephson junction devices made from free-standing InAs nanosheets. The nanosheets are grown by molecular beam epitaxy, and the Josephson junction devices are fabricated by directly contacting the nanosheets with superconductor Al electrodes. The fabricated devices are explored by low-temperature carrier transport measurements.

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The chemical bonding at the interface between compound semiconductors and metals is central in determining electronic and optical properties. In this study, new opportunities for controlling this are presented for nanostructures. We investigate Bi adsorption on 2D wurtzite InAs (112̄0) nanosheets and find that temperature-controlled Bi incorporation in either anionic- or cationic-like bonding is possible in the easily accesible range between room temperature and 400 °C.

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SmB, which opens up an insulating bulk gap due to hybridization between itinerant d-electrons and localized f-electrons below a critical temperature, turns out to be a topological Kondo insulator possessing exotic conducting states on its surface. However, measurement of the surface-states in SmB draws controversial conclusions, depending on the growth methods and experimental techniques used. Herein, we report anisotropic magnetoresistance (AMR) observed in the Kondo energy gap of a single SmB nanowire that is immune to magnetic dopant pollution and features a square cross-section to show high-symmetry crystal facets.

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The limit of dynamic endurance during repetitive contractions has been referred to as the point of muscle fatigue, which can be measured by mechanical and electrophysiological parameters combined with subjective estimates of load tolerance for revealing the human real-world capacity required to work continuously. In this study, an isotonic muscular endurance (IME) testing protocol under a psychophysiological fatigue criterion was developed for measuring the retentive capacity of the power output of lower limb muscles. Additionally, to guide the development of electrophysiological evaluation methods, linear and non-linear techniques for creating surface electromyography (sEMG) models were compared in terms of their ability to estimate muscle fatigue.

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We identified the strength cutpoints concerning mobility impairment, then identified the muscle mass cutpoints concerning weakness, and compared the results with other diagnostic criteria to develop the clinical diagnostic criteria associated with functional impairment. In 7583 elderly people, classification and regression tree (CART) and receiver operating characteristic curve (ROC) analyses were used for determining cutpoints for handgrip strength (HGS) and appendicular lean mass (ALM) indices associated with slowness or weakness. Logistic regressions were then used to quantify the strength of the association between muscle mass (or strength) categories and weakness (or slowness).

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Background: It is crucial to assess age-related muscle mass changes and derived indices differences in geriatric medicine. We aimed to develop and validate four bioimpedance analysis (BIA) prediction equations against dual-energy X-ray absorptiometry (DEXA) and magnetic resonance image (MRI) in estimating skeletal muscle mass and to compare the differences among skeletal muscle mass indices, cutoff values, and corresponding prevalence rates of low muscle mass for assessing sarcopenia in Chinese adults.

Methods: We measured the height (Ht), weight (Wt), appendicular lean mass (ALM) or skeletal muscle mass (ASM), total lean body mass (LBM) or skeletal muscle mass (TSM) obtained using DEXA or MRI, and a multi-frequency BIA (BCA ;50, 250 kHz), in 371 adults aged 18.

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A variety of infrared applications rely on semiconductor superlattices, including, notably, the realization of high-power, compact quantum cascade lasers. Requirements for atomically smooth interface and limited lattice matching options set high technical standards for fabricating applicable heterostructure devices. The semiconductor twinning superlattice (TSL) forms in a single compound with periodically spaced twin boundaries and sharp interface junctions and can be grown with convenient synthesis methods.

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Methods: circRNA expression was analysed in six cerebrospinal fluid (CSF) samples from three patients of the infectious and noninfectious phases using an Arraystar Human circRNA Array. Differentially altered circRNAs were validated by quantitative real-time polymerase chain reaction (qRT-PCR) in the 66 CSF samples of 33 patients of the infectious and noninfectious phases. -test was used for statistical analysis.

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Article Synopsis
  • Cooper pair splitting (CPS) creates nonlocal correlations between normal conductors connected to a superconductor, which is essential for generating entangled electron pairs and studying Majorana fermions without needing a magnetic field.
  • This study focuses on CPS using a Josephson junction made from gate-tunable ballistic InAs double nanowires, where results show that interwire superconductivity is stronger than intrawire superconductivity.
  • The findings reveal that the CPS effect is linked to one-dimensional electron-electron interactions, providing a foundation for advancing CPS techniques and engineering Majorana fermions in similar nanowire setups.
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Contamination is a major concern in surface and interface technologies. Given that graphene is a 2D monolayer material with an extremely large surface area, surface contamination may seriously degrade its intrinsic properties and strongly hinder its applicability in surface and interfacial regions. However, large-scale and facile treatment methods for producing clean graphene films that preserve its excellent properties have not yet been achieved.

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Article Synopsis
  • Quantum confined devices in 3D topological insulators hold potential for advancing spintronics and quantum computing, but their realization has faced challenges due to energy gap limitations.
  • Recent efforts resulted in successful single-electron transistor devices made from Bi Te nanoplates, employing advanced nanofabrication techniques.
  • The devices exhibit functioning tunneling junctions and clear Coulomb current oscillations, paving the way for controlled quantum systems that can enhance research in topological states and low-energy technologies.
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SmB nanowires, as a prototype of nanostructured topological Kondo insulator, have shown rich novel physical phenomena relating to their surface. Catalyst-assisted chemical vapor deposition (CVD) is a common approach to prepare SmB nanowires and Ni is the most popular catalyst used to initiate the growth of SmB nanowires. Here, we study the effect of growth mechanism on the surface of SmB nanowires synthesized by CVD.

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Low-dimensional narrow-band-gap III-V semiconductors are key building blocks for the next generation of high-performance nanoelectronics, nanophotonics, and quantum devices. Realizing these various applications requires an efficient methodology that enables the material dimensional control during the synthesis process and the mass production of these materials with perfect crystallinity, reproducibility, low cost, and outstanding electronic and optoelectronic properties. Although advances in one- and two-dimensional narrow-band-gap III-V semiconductors synthesis, the progress toward reliable methods that can satisfy all of these requirements has been limited.

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Low-dimensional narrow band gap III-V compound semiconductors, such as InAs and InSb, have attracted much attention as one of promising platforms for studying Majorana zero modes and non-Abelian statistics relevant for topological quantum computation. So far, most of experimental studies were performed on hybrid devices based on one-dimensional semiconductor nanowires. In order to build complex topological circuits toward scalable quantum computing, exploring high-mobility two-dimensional (2D) III-V compound electron system with strong spin-orbit coupling is highly desirable.

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Unlabelled: Muscle strength and function declined more than the concomitant loss of muscle mass. Measures of muscle strength and function are an effective way to assess functional ability and physical health in older people. A healthy lifestyle such as physical exercise, good nutrition, and higher BMI can benefit older people.

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Quantum Griffiths singularity was theoretically proposed to interpret the phenomenon of divergent dynamical exponent in quantum phase transitions. It has been discovered experimentally in three-dimensional (3D) magnetic metal systems and two-dimensional (2D) superconductors. But, whether this state exists in lower dimensional systems remains elusive.

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We report on experimental detection of the spin-orbit interaction field in an InAs nanowire double quantum dot device. In the spin blockade regime, leakage current through the double quantum dot is measured and is used to extract the effects of spin-orbit interaction and hyperfine interaction on spin state mixing. At finite magnetic fields, the leakage current arising from the hyperfine interaction can be suppressed, and the spin-orbit interaction dominates spin state mixing.

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Wrinkles are ubiquitous for graphene films grown on various substrates by chemical vapor deposition at high temperature due to the strain induced by thermal mismatch between the graphene and substrates, which greatly degrades the extraordinary properties of graphene. Here we show that the wrinkle formation of graphene grown on Cu substrates is strongly dependent on the crystallographic orientations. Wrinkle-free single-crystal graphene was grown on a wafer-scale twin-boundary-free single-crystal Cu(111) thin film fabricated on sapphire substrate through strain engineering.

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Wafer-sized single-crystalline Cu (100) surface can be readily achieved on stacked polycrystalline Cu foils via simple oxygen chemisorption-induced reconstruction, enabling fast growth of large-scale millimeter-sized single-crystalline graphene arrays under molecular flow. The maximum growth rate can reach 300 μm min , several orders of magnitude higher than previously reported values for millimeter-sized single-crystalline graphene growth on Cu foils.

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We reported here a selectively additive process to fabricate nanoscale openings of an Si (111) surface from an SiO2 barrier layer. Such nanoscale openings are made for the growth of vertical III-V nanowires. The Si (111) surface protected by a patterned SiNx layer was thermally oxidized, which resulted in a selectively added SiO2 barrier layer.

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