Fault diagnosis of mechanical drives under non-stationary conditions based on manifold learning of kernel mapping

For the detection of mechanical faults under the operating conditions of varying speeds and loads (such as wind turbines, excavators or helicopters, etc.), a new method for extracting the low-dimensional embedding of vibration data sets of mechanical drives under variable operation conditions is proposed. The hypothesis is that the space spanned by a set of vibration signals can be captured in a varying condition, to a close approximation, by a low-dimensional, nonlinear manifold. This paper presents a method to learn such a low-dimensional manifold from a given data set. The embedding manifold generated by vibration signals can be constructed from the feature set of parameters. Taking the variable operation condition into consideration, the kernel mapping is also introduced to improve the identification of submanifolds in terms of the projection distance. With the kernel mapping, the manifold coordinates can accurately capture the differences of the varying operation conditions. Experimental vibration signals obtained from normal and chipped tooth fault of gearbox in varying operation conditions are analyzed in this study. Results show that the proposed method is superior in identifying fault patterns and effective for gearbox condition monitoring

Control spiral wave dynamics using feedback signals from line detectors

We numerically study trajectories of spiral-wave-cores in excitable systems modulated proportionally to the integral of the activity on the straight line, several or dozens of equi-spaced measuring points on the straight line, the double-line and the contour-line. We show the single-line feedback results in the drift of core center along a straight line being parallel to the detector. An interesting finding is that the drift location in $y$ is a piecewise linear-increasing function of both the feedback line location and time delay. Similar trajectory occurs when replacing the feedback line with several or dozens of equi-spaced measuring points on the straight line. This allows to move the spiral core to the desired location along a chosen direction by measuring several or dozens of points. Under the double-line feedback, the shape of the tip trajectory representing the competition between the first and second feedback lines is determined by the distance of two lines. Various drift attractors in spiral wave controlled by square-shaped contour-line feedback are also investigated. A brief explanation is presented.Comment: 6 pages and 7 figures; Accepted for publication in EPL; Figs.5 and 6 are in JPG forma

Concept for a Future Super Proton-Proton Collider

Following the discovery of the Higgs boson at LHC, new large colliders are being studied by the international high-energy community to explore Higgs physics in detail and new physics beyond the Standard Model. In China, a two-stage circular collider project CEPC-SPPC is proposed, with the first stage CEPC (Circular Electron Positron Collier, a so-called Higgs factory) focused on Higgs physics, and the second stage SPPC (Super Proton-Proton Collider) focused on new physics beyond the Standard Model. This paper discusses this second stage.Comment: 34 pages, 8 figures, 5 table

Identification of Genes Directly Involved in Shell Formation and Their Functions in Pearl Oyster, Pinctada fucata

Mollusk shell formation is a fascinating aspect of biomineralization research. Shell matrix proteins play crucial roles in the control of calcium carbonate crystallization during shell formation in the pearl oyster, Pinctada fucata. Characterization of biomineralization-related genes during larval development could enhance our understanding of shell formation. Genes involved in shell biomineralization were isolated by constructing three suppression subtractive hybridization (SSH) libraries that represented genes expressed at key points during larval shell formation. A total of 2,923 ESTs from these libraries were sequenced and gave 990 unigenes. Unigenes coding for secreted proteins and proteins with tandem-arranged repeat units were screened in the three SSH libraries. A set of sequences coding for genes involved in shell formation was obtained. RT-PCR and in situ hybridization assays were carried out on five genes to investigate their spatial expression in several tissues, especially the mantle tissue. They all showed a different expression pattern from known biomineralization-related genes. Inhibition of the five genes by RNA interference resulted in different defects of the nacreous layer, indicating that they all were involved in aragonite crystallization. Intriguingly, one gene (UD_Cluster94.seq.Singlet1) was restricted to the ‘aragonitic line’. The current data has yielded for the first time, to our knowledge, a suite of biomineralization-related genes active during the developmental stages of P.fucata, five of which were responsible for nacreous layer formation. This provides a useful starting point for isolating new genes involved in shell formation. The effects of genes on the formation of the ‘aragonitic line’, and other areas of the nacreous layer, suggests a different control mechanism for aragonite crystallization initiation from that of mature aragonite growth

Controlling chaos by a modified straight-line stabilization method

PACS. 05.45.+a Nonlinear dynamics and nonlinear dynamical systems – 05.45.Gg Control of chaos, applications of chaos – 05.45.Pq Numerical simulations of chaotic models,

Protamine and BSA–dextran complex emulsion improves oral bioavailability and anti-tumor efficacy of paclitaxel

Food protein and polysaccharide complex emulsions are safe carriers of hydrophobic drugs and nutrients. To improve oral bioavailability and therapeutic/healthy efficacy of hydrophobic drugs and nutrients, herein, protamine (PRO), a cationic cell-penetrating peptide, was introduced into protein and polysaccharide complex emulsion. The electrostatic complex of PRO and BSA–dextran conjugate (BD) produced by Maillard reaction was used as emulsifier to produce oil-in-water emulsion (@BD/PRO). The BSA molecules were crosslinked at the oil–water interface by a heat treatment and the PRO chains were simultaneously anchored in the interface. BD emulsion (@BD) without PRO was produced for comparation. Paclitaxel (PTX), a hydrophobic antineoplastic drug, was encapsulated in the emulsions with 99% loading efficiency and 6.4% loading capacity. The emulsions had long-term stability. The bioavailability and H22 tumor inhibition efficacy of PTX@BD/PRO were 40% and 70% higher than those of PTX@BD, respectively, after oral administration in the mice. More importantly, orally administrated PTX@BD/PRO had the same anti-tumor efficacy as intravenously injected commercial PTX injection. No abnormality was observed in the main organs of the mice after consecutive oral administration of PTX@BD/PRO. This study indicates that @BD/PRO is an excellent carrier of hydrophobic drugs/nutrients and is suitable for long-term oral administration

Liver-targeted delivery of insulin-loaded nanoparticles via enterohepatic circulation of bile acids

Liver is the primary acting site of insulin. In this study, we developed innovative nanoparticles for oral and liver-targeted delivery of insulin by using enterohepatic circulation of bile acids. The nanoparticles were produced from cholic acid and quaternary ammonium modified chitosan derivative and hydroxypropyl methylcellulose phthalate (HPMCP). The nanoparticles had a diameter of 239 nm, an insulin loading efficiency of 90.9%, and a loading capacity of 18.2%. Cell culture studies revealed that the cholic acid groups effectively enhanced the transport of the nanoparticles through Caco-2 cell monolayer and greatly increased the absorption of the nanoparticles in HepG-2 cells via bile acid transporter mechanism. Ex vivo fluorescence images of ileum section, gastrointestinal tract, and liver demonstrated that the HPMCP increased the mucoadhesion of the nanoparticles in ileum, and the cholic acid groups facilitated the absorptions of the nanoparticles in both ileum and liver by use of bile acid transporters via enterohepatic circulation of bile acids. The therapy for diabetic mice displayed that the oral nanoparticle group could maintain hypoglycemic effect for more than 24 h and its pharmacological availability was about 30% compared with the insulin injection group. For the first time, this study demonstrates that using enterohepatic circulation of bile acids is an effective strategy for oral delivery of insulin

Second-order sliding mode control for high-dimension uncertain multivariable systems

A second-order non-singular terminal sliding mode (NTSM) controller with hierarchical structure, is proposed for a class of uncertain high-dimensional multivariable systems. By two non-singular state transformations, the system is firstly converted into decomposed block controllable form, consisting of an input-output subsystem and an internal one. A second-order NTSM controller is designed to force the input-output subsystem to converge to zero with characteristics of fast and better tracking precision, as well as free-chattering. Meanwhile, the internal subsystem is converted into zero dynamic subsystem, which asymptotical stability and finally that of the original system is guaranteed by eigenvalue configuration method. The simulation results are presented to validate the designed method. © 2011 IEEE

Novel Asymmetric Pyramid Aggregation Network for Infrared Dim and Small Target Detection

Robust and efficient detection of small infrared target is a critical and challenging task in infrared search and tracking applications. The size of the small infrared targets is relatively tiny compared to the ordinary targets, and the sizes and appearances of the these targets in different scenarios are quite different. Besides, these targets are easily submerged in various background noise. To tackle the aforementioned challenges, a novel asymmetric pyramid aggregation network (APANet) is proposed. Specifically, a pyramid structure integrating dual attention and dense connection is firstly constructed, which can not only generate attention-refined multi-scale features in different layers, but also preserve the primitive features of infrared small targets among multi-scale features. Then, the adjacent cross-scale features in these multi-scale information are sequentially modulated through pair-wise asymmetric combination. This mutual dynamic modulation can continuously exchange heterogeneous cross-scale information along the layer-wise aggregation path until an inverted pyramid is generated. In this way, the semantic features of lower-level network are enriched by incorporating local focus from higher-level network while the detail features of high-level network are refined by embedding point-wise focus from lower-level network, which can highlight small target features and suppress background interference. Subsequently, recursive asymmetric fusion is designed to further dynamically modulate and aggregate high resolution features of different layers in the inverted pyramid, which can also enhance the local high response of small target. Finally, a series of comparative experiments are conducted on two public datasets, and the experimental results show that the APANet can more accurately detect small targets compared to some state-of-the-art methods