27 research outputs found
A Novel Method for the Fault Diagnosis of a Planetary Gearbox based on Residual Sidebands from Modulation Signal Bispectrum Analysis
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
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
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
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Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks
无线传感器网络,作为全球未来十大技术之一,集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术,可实时感知、采集、处理、传输网络分布区域内的各种信息数据,在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议,并针对大规模的无线传感器网络设计了一种树状路由协议,它根据节点地址信息来形成路由,从而简化了复杂繁冗的路由表查找和维护,节省了不必要的开销,提高了路由效率,实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR(AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位:工学硕士院系专业:信息科学与技术学院通信工程系_通信与信息系统学号:2332007115216
Refractive index of [100] lithium fluoride under shock pressures up to 151 GPa
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
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
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
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
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