A motor bearing fault diagnosis model based on multi-adversarial domain adaptation.

In response to the weakened capability of feature transfer and parameter distribution alignment across domains due to significant differences in data distribution collected by different devices, this paper constructs a motor bearing fault diagnosis model based on multi-adversarial domain adaptation. Initially, an improved residual network is employed as the feature extraction module to enhance feature extraction capabilities. It then incorporates a Selective Kernel Network (SKNet) to implement attention mechanisms on convolutional kernels, and a Global Context Network (GCNet) to effectively utilize global contextual information for re-weighting across different channels.

Miniaturized fiber Bragg grating accelerator sensors for low-frequency vibration monitoring.

Acceleration monitoring is an important technical means of seismic monitoring, oil exploration, deep well observation, etc. A miniaturized fiber Bragg grating (FBG) acceleration sensor with three cantilever beams is proposed against the fact that it is difficult for fiber-optic sensors to meet the requirements for low-frequency vibration monitoring. First, the model of the FBG acceleration sensor was built and theoretically analyzed; second, the effect of structural parameters on sensor sensitivity and natural frequency was analyzed, and the sensors were subjected to static stress analysis and modal simulation analysis through the ANSYS finite element analysis software; finally, the real sensors were developed and subjected to performance tests with a low-frequency vibration test system.

Theoretical Kinetics studies of isoprene peroxy radical chemistry: The fate of Z-δ-(4-OH, 1-OO)-ISOPOO radical.

The OH radical recycling mechanism in isoprene oxidation is one of the most exciting topics in atmospheric chemistry, and the corresponding studies expand our understanding of oxidation mechanisms of volatile organic compounds in the troposphere and provide reliable evidence to improve and develop conventional atmospheric models. In this work, we performed a detailed theoretical kinetics study on the Z-δ-(4-OH, 1-OO)-ISOPOO radical chemistry, which is proposed as the heart of OH recycling in isoprene oxidation. With the full consideration of its accumulation and consumption channels, we studied and discussed the fate of Z-δ-(4-OH, 1-OO)-ISOPOO radical by solving the energy-resolved master equation over a broad range of conditions, including not only room temperatures but also high temperatures of a forest fire or low temperatures and pressures of the upper troposphere.

Comprehensive Theoretical Study on Four Typical Intramolecular Hydrogen Shift Reactions of Peroxy Radicals: Multireference Character, Recommended Model Chemistry, and Kinetics.

Intramolecular hydrogen shift reactions in peroxy radicals (RO → QOOH) play key roles in the low-temperature combustion and in the atmospheric chemistry. In the present study, we found that a mild-to-moderate multireference character of a potential energy surface (PES) is widely present in four typical hydrogen shift reactions of peroxy radicals (RO, R = ethyl, vinyl, formyl methyl, and acetyl) by a systematic assessment based on the diagnostic, %TAE diagnostic, diagnostic, and contribution of the dominant configuration of the reference CASSCF wavefunction (). To assess the effects of these inherent multireference characters on electronic structure calculations, we compared the PESs of the four reactions calculated by the multireference method CASPT2 in the complete basis set (CBS) limit, single-reference method CCSD(T)-F12, and single-reference-based composite method WMS.

Master equation study of hydrogen abstraction from HCHO by OH a chemically activated intermediate.

The abstraction reaction of hydrogen from formaldehyde by OH radical plays an important role in formaldehyde oxidation. The reaction involves a bimolecular association to form a chemically activated hydrogen-bonded reaction complex followed by a unimolecular reaction of the complex to generate the products. The reaction rate is usually considered to be pressure-independent by assuming equilibrium between the reactants and the complex.

Evaluation of digestibility differences for apple polyphenolics using in vitro elderly and adult digestion models.

We evaluated the in vitro digestibility of apple polyphenols mimicking elderly and adult digestion models (dynamic and static systems). The digestibility of total apple polyphenols in small intestine was much higher in the adult dynamic system (62 μg/100 g fresh apple) compared to the static system (20 μg/100 g fresh apple) and elderly dynamic digestion conditions (33 μg/100 g fresh apple). Elderly in vitro static digestion showed better antioxidant activity than the adult system (OH and ABTS methods).

Purification, structural characterization, and anticoagulant activity evaluation of chondroitin sulfate from codfish (Gadus macrocephalus) bones.

Chondroitin sulfate (CCS) was purified from discarded codfish (Gadus macrocephalus) bones, and its chemical structure and anticoagulant activity were assessed. CCS was obtained via enzymatic lysis and ion-exchange column chromatography, with a yield of approximately 0.15%.

Observing Intramolecular Vibrational Energy Redistribution via the Short-Time Fourier Transform.

Intramolecular vibrational energy relaxation (IVR) is important in many problems in chemical physics. Here, we apply the short-time Fourier transform method for analyzing IVR with classical dynamics. Calculating time-dependent Fourier transforms to perform such an analysis requires extending the usual Fourier transform method, and we do that here.

Pressure-dependent kinetics of the -xylene reaction with OH radicals.

OH-initiated oxidation reactions of -xylene are widely concerned both in combustion and atmospheric chemistry. In this work, the kinetics of the -xylene reaction with OH radicals has been studied systematically in a wide temperature range of 220-3000 K for the high-pressure limit and several selected pressures from 1 torr to 500 atm using multi-structural variational transition state theory with the small-curvature tunneling approximation (MS-CVT/SCT) and the system-specific quantum Rice-Ramsperger-Kassel (SS-QRRK) method. The calculations fully considered various factors which could affect the accuracy of the calculated rate constants including anharmonicity of both low- and high-frequency modes and multiple low-energy conformers, variational effect, and tunneling.

Mechanisms underlying operational energy consumption of buildings for low carbon city construction: A review.

With rapid urbanization, the increasing building stock, building operation energy consumption and the corresponding carbon emissions have become the important factors restricting the sustainable development of cities. To reduce energy consuming, it is necessary to explore the mechanisms underlying building's operational energy consumption and carbon emission. Although previous studies have analyzed the influencing factors and driving mechanism of urban building carbon emission from different perspectives, a systematical review of the relevant studies which could provide comprehensive guidance for building energy conservation and consumption reduction is fairly scarce.

Energy Dependence of Ensemble-Averaged Energy Transfer Moments and Its Effect on Competing Decomposition Reactions.

We carried out a direct dynamics study on the internal-energy dependence of the ensemble-averaged energy transfer moments of the isobutyl radical in collisions with N bath gas. We find a linear dependence of the downward moment ⟨Δ⟩ and the root-mean-square moment on the initial internal energy, but the upward moment ⟨Δ⟩ is found to be independent of the molecule's internal energy. We improved the exponential-down relaxation model by including a linear dependence of ⟨Δ⟩ on the initial energy, and we used the improved treatment in the 1D master equation for isobutyl radical decomposition reactions and for a model of competitive reactions with a larger difference in barrier heights.

Phonon lasing with an atomic thin membrane resonator at room temperature.

Graphene has been considered as one of the best materials to implement mechanical resonators due to their excellent properties such as low mass, high quality factors and tunable resonant frequencies. Here we report the observation of phonon lasing induced by the photonthermal pressure in a few-layer graphene resonator at room temperature, where the graphene resonator and the silicon substrate form an optical cavity. A marked threshold in the oscillation amplitude and a narrowing linewidth of the vibration mode are observed, which confirms a phonon lasing process in the graphene resonator.

Low-Pressure Limit of Competitive Unimolecular Reactions.

Barker and Ortiz found unusual falloff effects in the flux coefficients of the competitive unimolecular reactions of 2-methylhexyl radicals, and they concluded that this might have important effects on the rate constants of reactions with higher thresholds. To study this effect, we carried out master equation calculations of the same reaction system to learn whether this effect shows up in measurable rate constants, and the answer is yes. We also studied specially designed mechanisms to reveal that the various reactive pathways connecting the reagents can have a large effect on the rate constants, causing them to be quite different than if the reactions proceeded independently, and that reactions with significantly higher barriers may nevertheless have larger rate constants.

Computational kinetics of the hydrogen abstraction reactions of n-propanol and iso-propanol by OH radical.

Propanol (n-propanol or iso-propanol (i-propanol)) is a promising clean-burning oxygenated fuel component and fuel additive. Understanding its reactions with OH radical is of great significance in both combustion and atmospheric chemistry. In this work, we calculate the rate constants and branching ratios of the hydrogen abstraction reactions of n-propanol and i-propanol by OH radical in a broad temperature range of 63-2000 K using the competitive canonical unified statistical (CCUS) model.

Kinetics of the Toluene Reaction with OH Radical.

We calculated the kinetics of chemical activation reactions of toluene with hydroxyl radical in the temperature range from 213 K to 2500 K and the pressure range from 10 Torr to the high-pressure limit by using multistructural variational transition state theory with the small-curvature tunneling approximation (MS-CVT/SCT) and using the system-specific quantum Rice-Ramsperger-Kassel method. The reactions of OH with toluene are important elementary steps in both combustion and atmospheric chemistry, and thus it is valuable to understand the rate constants both in the high-pressure, high-temperature regime and in the low-pressure, low-temperature regime. Under the experimental pressure conditions, the theoretically calculated total reaction rate constants agree well with the limited experimental data, including the negative temperature dependence at low temperature.

Quantum Effects on H Diffusion in Zeolite RHO: Inverse Kinetic Isotope Effect for Sieving.

We use canonical variational theory (CVT) with small-curvature tunneling (SCT) contributions to investigate quantum effects on the H diffusion process in the pure-silica zeolite RHO. At low temperature we find an inverse kinetic isotopic sieving effect in that the heavier isotopic species diffuses faster than the lighter one. Three quantum effects contribute to this kinetic isotope effect (KIE).

The Wnt/β-catenin signaling pathway mechanism for pancreatic cancer chemoresistance in a three-dimensional cancer microenvironment.

β-catenin is a key protein that is encoded by the gene in the Wnt signaling pathway. This study investigated the associations between β-catenin expression and implications for the efficacy of gemcitabine on pancreatic cancer cells in a three-dimensional (3-D) cancer microenvironment. For low β-catenin expression pancreatic carcinoma cells, the inhibition rates (IRs) for low, middle, and high doses of gemcitabine were 0.

miR-410-3p suppresses breast cancer progression by targeting Snail.

miR-410-3p acts as an oncogene or tumor-suppressor gene in various types of cancer. However, its role in breast cancer remains unknown. In the present study, expression of miR-410-3p in 30 breast cancer and paired adjacent normal tissues was detected by RT-qPCR.

Invasion Genetics of Woolly Apple Aphid (Hemiptera: Aphididae) in China.

In China, the woolly apple aphid, Eriosoma lanigerum (Hausmann), was first detected as an invasive species during the 1910s to 1930s, restricted to Shandong, Liaoning, and Yunnan Provinces. However, since the 1990s, the pest has spread into many other areas of China. To determine the possible spread routes of the recently established populations, the genetic diversity and genetic structure of 24 populations in 10 provinces were analyzed using eight microsatellite loci.

Protection effect of trigonelline on liver of rats with non-alcoholic fatty liver diseases.

Objective: To study the effect of trigonelline on the change of indicators of serum transaminase, lipoprotein and liver lipid of model rats with non-alcoholic fatty liver diseases and on the expression level of Bcl-2 and Bax proteins.

Methods: A total of 45 SD rats were randomly divided into the control group, model group and trigonelline intervention group. Rats in the control group were fed with the common diet, while rats in the model group and intervention group were fed with the high fat diet.

Age-related Changes of Posterior Tibial Slope and Its Roles in Anterior Cruciate Ligament Injury.

Nearly all previous studies in posterior tibial slope (PTS) and anterior cruciate ligament (ACL) injuries ignored age-related changes, and the published data are inconsistent. The objective of this study was to reveal age-related changes of PTS and its roles in ACL injury. Data for 2618 lower limbs were included initially based on the availability of lateral radiographs and a suitable femoro-tibial angle.

Population structure of the greenhouse whitefly, Trialeurodes vaporariorum (Westwood), an invasive species from the Americas, 60 years after invading China.

Though the greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) was introduced into China more than 60 years ago, the genetic diversity and structure of this exotic insect pest and virus vector have not been studied. To investigate the population genetic characteristics of this invasive species and to identify potential invasion routes, the genetic diversity and population structure of 17 collections of T. vaporariorum from nine provinces in China were analyzed using seven microsatellite loci.