27 research outputs found

    A Novel Method for the Fault Diagnosis of a Planetary Gearbox based on Residual Sidebands from Modulation Signal Bispectrum Analysis

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    This paper presents a novel method for the fault diagnosis of planetary gearboxes based on an accurate estimation of residual sidebands using a modulation signal bispectrum (MSB). The residual sideband resulting from the out-phase superposition of vibration waves from asymmetrical multiple meshing sources are much less influenced by gear errors than that of the in-phase sidebands. Therefore, with the accurate estimation by MSB they can produce accurate and consistent diagnosis, which are evaluated by both simulating and experimental studies. However, the commonly used in-phase sidebands have high amplitudes but include gear error effects, consequently leading to poor diagnostic results

    Modelling and Validation of a Regenerative Shock Absorber System

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    Abstract— For effective energy regeneration and vibration dampening, energy regenerative suspension systems have received more studies recently. This paper presents the dynamic modeling and a test system of a regenerative shock absorber system which converts vibration motion into rotary motion through the adjustment of hydraulic flow. Hydraulic circuit configuration achieves the one way flow and energy regeneration during both compression and extension strokes. The dynamic modeling is performed for the evaluation of design concept and the feasibility studies of regenerative shock absorber system theoretically. Based on simulated results, the efficiency of hydraulic transmission is optimized and validated in test system. The results show that the performance of hydraulic fluid, the features of rotary motion and the capability of energy regeneration are verified and compared between dynamic modeling and experiments. Meanwhile, the average power of 118.2W and 201.7W with the total energy conversion of 26.86% and 18.49% can be obtained based on experiments under sinusoidal inputs with 0.07854m/s and 0.1256m/s respectively

    Agents of May Fourth. Jing Yinyu, Xu Zhongnian, and the Early Introduction of Modern Chinese Literature in France

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    Jing Yinyu (1901-1931?) and Xu Zhongnian (1904-1981) played a pivotal role in the dissemination of modern Chinese literature in France at the turn of the 1930s. Best known as Lu Xun’s first translator into a Western language and a friend of Romain Rolland’s, Jing compiled the Anthologie des conteurs chinois modernes in 1929. In his Anthologie de la littérature chinoise. Des origines à nos jours, published in 1932, Xu also devoted a section to recent literary developments. By analyzing the nature of the two projects, the translated corpora, and their paratexts, I will describe the features of Jing’s and Xu’s dissemination of May Fourth literature in France and scrutinize their artistic and ideological stance vis-à-vis the new literary scene. Ultimately, I will attempt to pinpoint in what terms the two scholars-cum-translators’ agency contributed to foreign readers’ awareness of the cultural, social and political experience of the May Fourth Movement

    Refractive index of [100] lithium fluoride under shock pressures up to 151 GPa

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    Single-crystal lithium fluoride(LiF) is a widely used window material in shock wave experiments to maintain the shock stress on the sample surface. It is transparent under shock compression up to ∼200 GPa, allowing the interferometer to record the movement of the monitored surface. However, the interferometer techniques require knowing the accurate refractive index of LiF under shock compression to deduce the true particle velocity. Although the refractive index of LiF under shock compression has long been studied, different experimental results diverge, especially in the high pressure region. Here, we used iron as the standard material to measure the refractive index of [100] LiF up to 151 GPa using two-stage light gas gun. Our results show that for the 1550 nm light, the true particle velocity (utrue) has a linear dependence on the apparent particle velocity (uapp), utrue = 12.26(2.07)m/s + 0.7759(0.0005)uapp, when the apparent particle velocity, uapp > 0.38 km/s

    Modelling and Validation of a Regenerative Shock Absorber System

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    Abstract— For effective energy regeneration and vibration dampening, energy regenerative suspension systems have received more studies recently. This paper presents the dynamic modeling and a test system of a regenerative shock absorber system which converts vibration motion into rotary motion through the adjustment of hydraulic flow. Hydraulic circuit configuration achieves the one way flow and energy regeneration during both compression and extension strokes. The dynamic modeling is performed for the evaluation of design concept and the feasibility studies of regenerative shock absorber system theoretically. Based on simulated results, the efficiency of hydraulic transmission is optimized and validated in test system. The results show that the performance of hydraulic fluid, the features of rotary motion and the capability of energy regeneration are verified and compared between dynamic modeling and experiments. Meanwhile, the average power of 118.2W and 201.7W with the total energy conversion of 26.86% and 18.49% can be obtained based on experiments under sinusoidal inputs with 0.07854m/s and 0.1256m/s respectively

    Sound Velocity Anisotropy and Single‐Crystal Elastic Moduli of MgO to 43 GPa

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    Seismic anisotropy in the Earth's lower mantle likely results from a combination of elastic anisotropy and lattice preferred orientations of its main constituent minerals. As the second most abundant component of the lower mantle, ferropericlase has been widely studied, and the experimental results demonstrated, in general, a growing with pressure elastic anisotropy up to 1 Mbar. However, the unique measurements on the endmember (MgO) at comparable pressure conditions contradict the above observations and theoretical results. Here, time‐domain Brillouin scattering was applied to measure longitudinal sound velocities in single crystals of MgO compressed in diamond anvil cell. Velocities along two specific crystallographic directions, [100] and [111], were independently collected to 43 GPa. Applying the known bulk modulus, a complete set of single‐crystal elastic moduli, elastic anisotropy and aggregate shear modulus were derived. Our results revealed a steadily increasing with pressure elastic anisotropy at P>20 GPa, consistent with the previous theoretical predictions and measurements on ferropericlase with moderate amounts of iron

    Therapeutic and immunoregulatory effects of water-soluble alkaloids E2-a from Sophora moorcroftiana seeds as a novel potential agent against echinococcosis in experimentally protoscolex-infected mice

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    Abstract Novel compounds and more efficient treatment options are urgently needed for the treatment of cystic echinococcosis (CE), which is caused by Echinococcus granulosus. The decoction of Sophora moorcroftiana (Fabaceae) has been used to treat parasitosis for years in traditional Tibetan medicine. The aim of this study was to screen insecticidal water-soluble alkaloids from S. moorcroftiana seeds and evaluate the therapeutic effects against CE and the immune response induced by the alkaloidal fraction. Low polarity compounds (E2-a) were isolated from water-soluble alkaloid (E2) and matrine and sophocarpine were identified as major components. The E2-a fraction was more effective against protoscoleces than other constituents from S. moorcroftiana. After 20 weeks of secondary infection with protoscoleces, mice were orally treated with E2-a (100 mg/kg/day) for 6 weeks to evaluate therapeutic and immunoregulatory activities. Compared with the untreated group, E2-a treatment induced a significant reduction in cyst weight (mean 2.93 g) (p < 0.05) and an impaired ultrastructural modification of the cyst. Interestingly, the application of E2-a resulted in a significant increased frequency of CD3+CD4+ T-cell subsets and decreased frequency of CD3+PD-1+ T-cell subsets, compared with protoscolece-infected mice without treatment. The E2-a fraction of S. moorcroftiana can inhibit the cyst development of CE and boost the specific immune response by reducing the expression of PD-1 and accelerate the cytokine secretion of antigen-specific T-cells. All data suggest the E2-a fraction from S. moorcroftiana seeds may be used as a new potential therapeutic option against E. granulosus infection

    Willingness to accept COVID-19 vaccine among the elderly and the chronic disease population in China

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    A cross-sectional field survey was conducted from November 2020 to January 2021 among 7259 participants to investigate the public perception, willingness, and information sources for COVID-19 vaccination, with the focus on the elderly and non-communicable chronic disease (NCD) population. Multiple logistic regressions were performed to identify associated factors of the vaccination willingness. The willingness rate of the elderly to accept the future COVID-19 vaccine (79.08%) was lower than that of the adults aged 18–59 (84.75%). The multiple analysis didn't identify significant relationship between NCD status and the vaccination intention. The main reasons for vaccine hesitancy by the public were: concern for vaccine safety, low infection risk, waiting and seeing others getting vaccinated, concern of vaccine effectiveness and price. Their relative importance differed between adults aged 18–59 and the elderly, and between adults aged 18–59 with or without NCD. Perception for vaccination importance, vaccine confidence, and trust in health workers were significant predictors of the vaccination intention in both age groups. The elderly who perceived high infection risk or had trust in governments were more likely to accept the vaccine. Compared with the adults aged 18–59, the elderly used fewer sources for COVID-19 vaccination information and more trusted in traditional media and family, relatives, and friends for getting vaccination recommendations. To promote vaccine uptake, the vaccination campaigns require comprehensive interventions to improve vaccination attitude, vaccine accessibility and affordability, and tailor strategies to address specific concerns among different population groups and conducted via their trusted sources, especially for the elderly
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