In this paper, it is aimed to investigate semi-active suspension systems using magnetorheological (MR) fluid dampers for improving the ride quality of railway vehicles. A 17-degree-of-freedom (DOF) ...model of a full-scale railway vehicle integrated with the semi-active controlled MR fluid dampers in its secondary suspension system is proposed to cope with the lateral, yaw, and roll motions of the car body, trucks, and wheelsets. The governing equations combining the dynamics of the railway vehicle integrated with MR dampers in the suspension system and the dynamics of the rail track irregularities are developed and a linear quadratic Gaussian (LQG) control law using the acceleration feedback is adopted, in which the state variables are estimated from the measurable accelerations with a Kalman estimator. In order to evaluate the performances of the semi-active suspension systems based on MR dampers for railway vehicles, the random and periodical track irregularities are modelled with a uniform state-space formulation according to the testing data and incorporated into the governing equation of the railway vehicle integrated with the semi-active suspension system. Utilising the governing equations and the semi-active controller developed in this paper, the simulation and analysis are presented in Part II of this paper.
It is challenging to simultaneously achieve nearly full density and high strength in refractory alloys using selective laser melting (SLM). In this study, the achievement of ultrahigh-strength ...resulting from nearly full density has been reported in beta-type titanium alloy by controlling the melt pool mode in SLM. The melt pool mode was divided into the conduction and keyhole modes, which were determined from the macroscopic morphology of the melt pool in the SLMed Ti-34.2Nb-6.8Zr-4.9Ta-2.3Si (wt%) (TNZTS) alloy single tracks in combination with the keyhole threshold (P·V−0.5 = 251.3 W (m⋅s−1)−0.5) calculated theoretically. Compared with condition mode, the keyhole mode has higher porosity and inevitably causes poor mechanical property. Fortunately, by optimizing the SLM process parameters predicted via the keyhole threshold, an ultrahigh-strength and nearly full density (99.7%) TNZTS alloy with conduction mode was obtained by SLM. The alloy exhibited an ultrahigh compressive yield strength of 1286 MPa, which was higher than the majority of the beta-type titanium alloys reported so far. The microstructural analyses indicated that the ultrahigh-strength TNZTS alloy consisted of a thin shell-shaped (Ti, Nb, Zr)2Si (S2) phase (20–50 nm) around the columnar β-Ti grain boundaries together with an ultrafine dot shaped (Ti, Nb, Zr)5Si3 (S1) phase (50–300 nm) in the β-Ti matrix. The ultrahigh strength resulted from high-density dislocations and the effective dislocation blockage by the semi-coherent S1 and coherent S2 phases, thereby leading to the dislocation-strengthening and hardening effect. The strategy utilized in this study provides the fundamental guidelines for generating refractory metallic alloys with high density and excellent performance.
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Metal foils are extensively used for manufacturing microparts with a high depth-to-thickness ratio by microforming processes. Since there are few grains participating in the ...deformation of metal foil, the mechanical response of each individual grain intensively affects the deformation behavior and the quality of the formed micropart, which leads to strong anisotropy in microforming. To clarify the size effect on material anisotropy and the impact of scale-dependent plastic anisotropy on the formability of metal foil, a series of tensile experiments and geometrically scaled-down deep-drawing tests of SUS304 foil with different thicknesses of 50–200 μm and grain sizes of 10.2–80.5 μm were performed. The experimental results indicate that the anisotropy of flow stress, yield tensile ratio (i.e., ratio of the yield strength to the tensile strength) and elongation at angles of 0°, 45° and 90° to the rolling direction is prominently enhanced with decreasing thickness and that the anisotropy generally shows a substantial sensitivity to grain size. In addition, the abnormally increased hardening rate of flow behavior for metal foil with few grains in thickness direction arises from the deformation-induced transformation from austenite to martensite. The Lankford values in different orientations, the planar anisotropy and normal anisotropy coefficients decrease with increasing grain size and decreasing foil thickness. The foil manifests strong plastic anisotropy when the grain size is comparable to the foil thickness due to the dominant response of individual grains in terms of crystal orientation, texture, size and shape at a low value of t/d ratio (i.e., the ratio of the thickness to the grain size). Furthermore, several macroscale yield criteria are adopted to characterize the anisotropic phenomenon in the multi-scaled deep drawing process. The results suggest that the Yld2000-2d criterion is more suitable than Hill’48 and Von Mises functions to predict the anisotropic behavior of metal foil with a large number of grains involved in microforming. However, the prediction precision is worsened with decreasing t/d ratio, and the use of Yld2000-2d becomes problematic when the foil thickness is of the same magnitude as grain size, which is closely linked to the interactive effects of grain size, foil thickness and crystallographic texture in microscale plastic deformation.
Reactor neutrino experiments play a crucial role in advancing our knowledge of neutrinos. In this Letter, the evolution of the flux and spectrum as a function of the reactor isotopic content is ...reported in terms of the inverse-beta-decay yield at Daya Bay with 1958 days of data and improved systematic uncertainties. These measurements are compared with two signature model predictions: the Huber-Mueller model based on the conversion method and the SM2018 model based on the summation method. The measured average flux and spectrum, as well as the flux evolution with the ^{239}Pu isotopic fraction, are inconsistent with the predictions of the Huber-Mueller model. In contrast, the SM2018 model is shown to agree with the average flux and its evolution but fails to describe the energy spectrum. Altering the predicted inverse-beta-decay spectrum from ^{239}Pu fission does not improve the agreement with the measurement for either model. The models can be brought into better agreement with the measurements if either the predicted spectrum due to ^{235}U fission is changed or the predicted ^{235}U, ^{238}U, ^{239}Pu, and ^{241}Pu spectra are changed in equal measure.
Objective
Chronic inflammation is recognized as a risk factor for colorectal cancer (CRC) development. Baicalin (BI), a major constituent in an anti-inflammatory herb
Scutellaria baicalensis
, can be ...biotransformed into baicalein (BE) by the intestinal microbiota. We evaluated the anti-inflammation and anti-CRC effects of the metabolite BE.
Methods
The in vitro biotransformation by human intestinal microbiota from BI into BE has been determined with HPLC. Using a gut-specific
Apc
Min/
+
mouse model, the effects of oral BE on the life span, organ index, and tumor multiplicity were evaluated. The expressions of inflammatory cytokines were determined using ELISA. To verify the in vivo data, the anti-inflammatory and antiproliferative effects of BE were determined with an in vitro cell model.
Results
HPLC analysis showed that BI was quickly transformed into BE by the intestinal microbiota. Oral BE (30 mg/kg/day) significantly increased the life span, from 125.2 to 218.4 days (
P
< 0.01%). BE treatment also decreased intestine index and increased spleen index. Compared with the model group, following BE treatment, tumor numbers were significantly reduced in the small intestine and colon (
P
< 0.01,
P
< 0.05, respectively). In the gut tissues, BE treatment significantly reduced inflammatory cytokine levels such as IL-1β, IL-2, IL-6, IL-10, G-CSF, and GM-CSF. In vitro data supported our in vivo results that the anti-CRC effects of BE were via the inhibition of gut inflammation and induction of cancer cell death.
Conclusion
Our results suggest that the parent compound BI can be quickly converted into its microbial metabolite BE, which has stronger bioactive effects than BI. Baicalein is an active chemopreventive metabolite for inflammatory associated CRC.
We have developed and implemented an iterative algorithm of flux calibration for the LAMOST Spectroscopic Survey of the Galactic anticentre (LSS-GAC). For a given LSS-GAC plate, the spectra are first ...processed with a set of nominal spectral response curves (SRCs) and used to derive initial stellar atmospheric parameters (effective temperature T
eff, surface gravity log g and metallicity Fe/H) as well as dust reddening E(B − V) of all targeted stars. For each of the 16 spectrographs, several F-type stars with good signal-to-noise ratios are selected as flux standard stars for further, iterative spectral flux calibration. Comparison of spectrophotometric colours, deduced from the flux-calibrated spectra, with the photometric measurements yield average differences of 0.02 ± 0.07 and −0.04 ± 0.09 mag for (g − r) and (g − i), respectively. The relatively large negative offset in (g − i) is because we have opted not to correct for the telluric bands, most notably the atmospheric A band in the wavelength range of the i band. Comparison of LSS-GAC multi-epoch observations of duplicate targets indicates that the algorithm has achieved an accuracy of about 10 per cent in relative flux calibration for the wavelength range 4000–9000 Å. The shapes of SRCs deduced for individual LAMOST spectrographs vary by up to 30 per cent for a given night, and larger for different nights, indicating that the derivation of SRCs for the individual plates is essential to achieve accurate flux calibration for the LAMOST spectra.
Bats are asymptomatic reservoir hosts for several highly pathogenic viruses. Understanding this enigmatic relationship between bats and emerging zoonotic viruses requires tools and approaches which ...enable the comparative study of bat immune cell populations and their functions. We show that bat genomes have a conservation of immune marker genes which delineate phagocyte populations in humans, while lacking key mouse surface markers such as Ly6C and Ly6G. Cross-reactive antibodies against CD44, CD11b, CD14, MHC II, and CD206 were multiplexed to characterize circulating monocytes, granulocytes, bone-marrow derived macrophages (BMDMs) and lung alveolar macrophages (AMs) in the cave nectar bat Eonycteris spelaea. Transcriptional profiling of bat monocytes and BMDMs identified additional markers - including MARCO, CD68, CD163, CD172α, and CD88 - which can be used to further characterize bat myeloid populations. Bat cells often resembled their human counterparts when comparing immune parameters that are divergent between humans and mice, such as the expression patterns of certain immune cell markers. A genome-wide comparison of immune-related genes also revealed a much closer phylogenetic relationship between bats and humans compared to rodents. Taken together, this study provides a set of tools and a comparative framework which will be important for unravelling viral disease tolerance mechanisms in bats.
Abstract
In order to improve the identification efficiency and accuracy of distribution network ground fault identification methods, this paper proposes a distribution network ground fault ...identification method based on MMC injection detection signal strategy. Extract the fault information of distribution network grounding line, calculate the current component of three-phase current, and obtain the grounding fault data of distribution network.The detection current of distribution network is obtained by injection signal detection strategy. The fault information matrix is formed by using the detection current information, and the time-frequency characteristics of MMC injection detection signal strategy are obtained according to the actual situation.The wavelet transform is used to remove the clutter in the fault feature vector, and the normalized processing is used to obtain and process the ground fault vector.According to the wavelet function, the characteristics of the distribution network ground fault signal are determined. Cassie model and Mayr model are used to obtain the final distribution network ground fault identification model to realize the distribution network ground fault identification.The experimental results show that the accuracy of the method can reach 96.1%, and the time of fault identification is only 25s. The above results show that the method can effectively improve the effectiveness of distribution network ground fault identification.
Room-temperature plasticity in metallic glasses (MGs) is commonly associated with local structural heterogeneity; however, direct observation of the subtle structural change caused by plasticity is ...vitally important but the data are extremely scarce. Based on dynamic atomic force microscopy (DAFM), here we show that plasticity-induced structural evolution in a Zr-Ni MG can be revealed via nano-scale viscoelastic contacts between an AFM tip and plastically deformed MG surface layers. Our experimental results clearly show a spatial amplification of the nano-scale structural heterogeneity caused by the distributed plastic flow, which can be linked to the limited growth, reorientation and agglomeration of some nano-scale energy-absorbing regions, which are reminiscent of the behavior of the defect-like regions with non-affine deformation as conceived in many theories and models. Furthermore, we are able to experimentally extract the thermodynamic properties of these nano-scale regions, which possess an energy barrier of 0.3-0.5 eV, about half of that for a typical shear transformation event that usually occurs at the onset of plasticity. The outcome of our current work sheds quantitative insights into the correlation between plasticity and structural heterogeneity in MGs.
In an extension of the existing paradigm on the benefits of innovative behavior for organizations, this study addresses the negative effects of innovative behavior. Guided by psychological detachment ...theory, we propose that both displaying innovative behavior and witnessing others’ innovative behavior make it difficult for workers to psychologically distance themselves from innovation matters, engendering strain reactions (e.g., sleep problems, hostility). Those with more proactive personalities may be more likely to experience these detachment difficulty problems after displaying or witnessing innovative behavior. To test these premises, we conducted two studies. In the pilot study (N = 104 employee–coworker dyads), we gathered both quantitative and qualitative data to show that innovative behavior predicts detachment difficulty above and beyond other job behaviors. In the main study, we collected data from 257 employee–coworker dyads over 5 weeks and analyzed them with an actor–partner interdependence model. The results are generally supportive, suggesting that further investigation of the unintended consequences of innovative behavior is warranted.
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