Publications by authors named "Faxin Li"

This study investigated the aroma-releasing mechanism of rose during the scenting process with black tea. By quantitative descriptive analysis of sensory evaluations, it was found that 20-h scenting optimized the floral fragrance accumulation while minimizing the undesirable green odors. Meanwhile, neryl alcohol, citronellol, rose oxide, geraniol, linalool, phenethyl alcohol, neryl acetate, citronellyl acetate, eugenol, methyleugenol, and phenethyl acetate were identified as the dominant contributors to the aroma profiles of rose black tea and rose petals.

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This paper proposes a novel method for motion multi-object matching and position estimation in the absence of salient features based on unsynchronized image sequences. Our proposed method aims to address the issues of traditional feature matching that requires static objects, salient features and the need for synchronized images when the epipolar constraint is used. Firstly, unsynchronized image sequences are captured using three calibrated cameras, and for each motion object, three spatial planes are established using multi-images.

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This study conducted a comprehensive analysis of the differences in the taste characteristics of hawk black tea and hawk white tea, exploring the intrinsic relationship between nonvolatile metabolites and these taste characteristics. The results revealed significant differences in taste properties of the two types of hawk tea. Hawk black tea mainly exhibits a fresh, sweet, and sweet aftertaste quality, whereas hawk white tea offers a mellow and pure taste.

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Ultrasonic fatigue testing is quite a useful tool for exploring the high-cycle and very-high-cycle fatigue properties of materials. Damping monitoring has been proved to be fairly effective in indicating the generated defects or damage in the testing specimen. In this work, two damping monitoring methods are comparatively studied, i.

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Uniaxial compression experiments of limestone-coal specimens at different inclination angles (0, 15, 30, 45, and 60°) were conducted using acoustic emission and three-dimensional, extension test digital image correlation, and full-field strain measurement systems to examine how dip angles affect deformation failure. The findings indicate that: (1) specimen groups demonstrate plastic yield characteristics in the pre-peak stage. However, slight variations exist due to inclination angles.

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In this work, all independent elastic coefficients, piezoelectric coefficients, and internal frictions of a single alpha-quartz crystal are determined at room temperature using our recently proposed partial-electrode electromechanical impedance spectroscopy (PE-EMIS). In PE-EMIS, the rectangular parallelepiped quartz sample with two small partial electrodes fabricated on a corner is self-excited/sensed. The conductance spectrum (equivalent to the acoustic resonance spectrum) measured by an impedance analyzer under a free boundary condition is noiseless, allowing the first 100 eigenmodes ranging from 50 to 310 kHz to be accurately fit.

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Bolter miners are being increasingly used. Unfortunately, this mining technology causes a considerable amount of air pollution (especially by methane and dust) during excavation. In this study, the multiphase coupling field of airflow-dust-methane for different distances between the pressure air outlet and the working face (L) was simulated by using the FLUENT software.

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Thermal stress is one of the major causes of failure of engineering structures and its measurement has attracted more attention in recent years. The ultrasonic wave method is very promising in stress measurement due to its non-destructive nature and easy manipulation. The traditional ultrasonic wave transducers require a coupling medium which would introduce large repeatability errors in travel time measurement and thus in the measured stress.

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Clarifying the microscale gas-water flow behaviors in a mixed wettability reservoir is of great importance for underground engineering. A numerical model of mixed wettability based on circular particles was constructed using the MATLAB stochastic distribution program, and the gas-water flow was simulated based on the phase-field method. The Navier-Stokes equations were solved by the finite element method.

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To determine all the material constants of a piezoelectric crystal using the IEEE resonance method or ultrasonic method, several samples with specific geometries and orientations are required, and the obtained results may be somewhat self-contradictory. The resonant ultrasound spectroscopy (RUS) can determine full material constants of a single piezoelectric sample by matching the numerically computed eigenfrequencies to the measured resonance spectrum. However, typically the usage of PZT transducers for excitation and reception makes the testing complicated and may add additional mass and damping.

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Guided wave tomography, as an advanced structural health monitoring (SHM) method, has offered a feasible solution to wall thickness quantification which is essential in petrochemical industries. However, previously used low-frequency Lamb waves (A and S) limit the resolution of tomography. Recently, the first-order shear horizontal guided wave (SH) was found very promising in tomography for its capability in resolution improvement.

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Strain amplitude dependent effects of materials/structures are very important in the field of material science and engineering and have been found to be extremely sensitive to defects or damage. In this work, a nonlinear electromechanical impedance spectroscopy (N-EMIS) technique is proposed to characterize the amplitude dependent internal frictions (ADIFs) and modulus defects (or resonance shift) of materials. First, a new experimental scheme called the on/off parallel resistor capacitor circuit is proposed to measure the N-EMIS of a piezoelectric transducer (PZT)-specimen composite system under high driving levels.

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Shear horizontal (SH) waves are of great importance in structural health monitoring (SHM) and nondestructive testing (NDT), since the lowest order SH wave in isotropic plates is non-dispersive. The SH waves in plates, circumferential SH waves and torsional waves in pipes have remarkable resemblances in dispersion characteristics and wave structures, so the latter two can also be called as SH waves in pipes. This paper reviews the state-of-the-art research on SH wave transducers for SHM and NDT.

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Article Synopsis
  • The study examined prescription habits and safety of oral NSAIDs in three Chinese hospitals, analyzing data from over 50,000 patients.
  • Most patients received NSAIDs only once, with a preference for single types, and saw fewer GI and cardiovascular complications with selective COX-2 inhibitors compared to traditional NSAIDs.
  • There was inconsistency in NSAID prescribing practices among at-risk patients, but selective COX-2 inhibitors were found to have a better safety profile than traditional options.
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Low-temperature cofired ceramic technology is the prerequisite for producing advanced integrated piezoelectric devices that enable modern micro-electromechanical systems because of merits such as high level of compactness and ultralow drive voltage. However, piezoceramic structure with shear-type outputs, as a most fundamental functional electronic element, has never been successfully fabricated into multilayer form by the cofired method for decades. Technical manufacture requirements of parallel applied electric fields and polarization are theoretically incompatible with intrinsically orthogonal orientations in naturally occurring shear modes.

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In this Note, first, the calculation errors of elastic moduli and internal frictions using the explicit formulas in the traditional and modified piezoelectric ultrasonic composite oscillator technique (PUCOT and M-PUCOT) are comparatively studied when the frequency match condition is not satisfied. Then, new implicit formulas free of frequency match are proposed for the three-component M-PUCOT. Finally, the measurement results on a lead zirconate titanate ferroelectric ceramic from room temperature to 500 °C by using the pervious explicit formulas and the new implicit formulas are compared.

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When estimating a structural health monitoring (SHM) system, its defect sensitivity and area/distance coverage are most important factors. For commonly used guided wave sparse array system, it usually requires a reference state as the baseline which is not available in many cases. In comparison, phased array technique typically does not need the baseline in simple structures and it had been successfully used in nondestructive testing (NDT).

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In modern industries, long-distance guided wave inspection has been routinely used for various types of pipelines. The usage of T(0,1) wave is always of great interests since it is the only non-dispersive wave mode in pipes. In this work, a pair of pitch-catch piezoelectric ring arrays were proposed for long-distance structural health monitoring (SHM) of buried pipes.

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Background: Prior studies have noted the importance of T cell immunoglobulin and mucin domain containing 4 (TIMD4) in various diseases and its functions on cell malignant behaviors. However, the biological function of TIMD4 in diffuse large B-cell lymphoma (DLBCL) is unknown.

Methods: Relative expression of TIMD4 was analyzed based on the GSE56315 array including 88 cases of human tissues.

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Shear modulus is one of the fundamental mechanical properties of materials, while its quick and accurate measurement is still a challenge. Here we proposed a method for shear modulus measurement based on torsional resonance using a piezoelectric torsional transducer bonded on a cylindrical specimen. Firstly, the torsional transducer was introduced which consists of two thickness poled, thickness shear (d) piezoelectric half-rings.

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In this work, a modified piezoelectric ultrasonic composite oscillator technique (M-PUCOT) is developed for measuring a material's elastic moduli and internal frictions, as a function of temperature. Different from the traditional PUCOT that employs two quartz bars as the drive and gauge, here, a single small piezoelectric transducer (PZT) ring is used to drive and sense longitudinal or torsional vibration in a cylinder specimen. Because of the strong piezoelectric effect and relatively large bandwidth of the PZTs compared to their quartz counterpart, the frequency match condition between the transducer and the specimen is not required in this M-PUCOT.

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Love waves are of great importance in geophysics, electronics, and engineering. Despite intensive studies on high-frequency Love waves for delay lines and chemical/biomedical sensors, moderate-frequency and low-frequency Love waves have seldom been investigated. Here, Love waves in a 2-mm-thick Plexiglas plate bonded on a 50-mm-thick aluminum block were successfully excited and received by using d and d shear mode PZT wafers.

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Guided wave based defects inspection is very promising in the field of structural health monitoring (SHM) and nondestructive testing (NDT) due to its less dissipation and thus long distance coverage. In comparison with the widely used Lamb waves, shear horizontal (SH) waves are relatively simple but less investigated probably due to the traditional notion that SH waves were usually excited by electromagnetic acoustic transducers (EMAT). In this work, we proposed a tunable method to excite single-mode bidirectional SH waves in plates using antiparallel thickness-shear (d) piezoelectric strips (APS).

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Guided wave based structural health monitoring (SHM) has been regarded as an effective tool to detect the early damage in large structures and thus avoid possible catastrophic failure. In recent years, Lamb wave phased array SHM technology had been intensively investigated while the inherent multi-mode and dispersive characteristic of Lamb waves limits its further applications. In comparison, the fundamental shear horizontal (SH) wave is non-dispersive with uncoupled displacements and thus more promising for defect detection.

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