To investigate the relationship between surface microstructure and wear mechanism in D2/U71Mn wheel-rail material under different contact stress conditions, rolling wear tests using a GPM-40 wear ...machine to simulate the wheel-rail operation was performed. After wear tests, an optical microscope (OM), scanning electron microscope (SEM) and micro-hardness testers were used to characterize the microstructure and fatigue wear cracks. The results show that the thickness of the plastic deformation layer and surface hardness is increased with the increase of contact stress. Under high contact stress condition (1200 MPa), the severe plastic deformation layer led to the formation of fatigue wear of wheel-rail samples. Under a contact stress of 700 MPa, the wear mechanism of samples is adhesive wear and wear rate is low. With the increase of contact stress, the fatigue cracks are gradually severe. Under a contact stress of 1200 MPa, the wear mechanism of samples becomes fatigue wear and the fatigue wear cracks cause the increase of wear rate. The fatigue wear can accelerate the wear failure of wheel-rail samples. The fatigue wear cracks of wheel samples are severer than that of rail samples due to both the rate of plastic strain and the content of proeutectoid ferrite.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Odorant binding proteins (OBPs) and chemosensory proteins (CSPs) play important roles in transporting semiochemicals through the sensillar lymph to olfactory receptors in insect antennae. In the ...present study, twenty OBPs and three CSPs were identified from the antennal transcriptome of Microplitis mediator. Ten OBPs (MmedOBP11-20) and two CSPs (MmedCSP2-3) were newly identified. The expression patterns of these new genes in olfactory and non-olfactory tissues were investigated by real-time quantitative PCR (qPCR) measurement. The results indicated that MmedOBP14, MmedOBP18, MmedCSP2 and MmedCSP3 were primarily expressed in antennae suggesting potential olfactory roles in M. mediator. However, other genes including MmedOBP11-13, 15-17, 19-20 appeared to be expressed at higher levels in body parts than in antennae. Focusing on the functional characterization of MmedCSP3, immunocytochemistry and fluorescent competitive binding assays were conducted indoors. It was found that MmedCSP3 was specifically located in the sensillum lymph of olfactory sensilla basiconca type 2. The recombinant MmedCSP3 could bind several types of host insects odors and plant volatiles. Interestingly, three sex pheromone components of Noctuidae insects, cis-11-hexadecenyl aldehyde (Z11-16: Ald), cis-11-hexadecanol (Z11-16: OH), and trans-11-tetradecenyl acetate (E11-14: Ac), showed high binding affinities (Ki = 17.24-18.77 μM). The MmedCSP3 may be involved in locating host insects. Our data provide a base for further investigating the physiological roles of OBPs and CSPs in M. mediator, and extend the function of MmedCSP3 in chemoreception of M. mediator.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This paper studies the visual-tracking (visual-servo) control problem for a free-floating space manipulator using an eye-in-hand camera for the capturing process, where the motion of the target ...spacecraft is unknown and the dynamics of the system are uncertain. A depth-independent matrix is developed to help design an observer for estimating the unknown positions of target points on the spacecraft in the inertial frame. The target points are used to estimate depth information for visual servo control. An adaptive controller is used to force the feature points on the target to converge onto the desired positions on the image plane as well as estimate the uncertain dynamic parameters. The Lyapunov approach is used to show asymptotic stability of the system and convergence of image errors. Finally, simulation results are presented to validate the performance of the proposed control algorithm.
Moving camera-based object tracking method for the intelligent transportation system (ITS) has drawn increasing attention. The unpredictability of driving environments and noise from the camera ...calibration, however, make conventional ground plane estimation unreliable and adversely affecting the tracking result. In this paper, we propose an object tracking system using an adaptive ground plane estimation algorithm, facilitated with constrained multiple kernel (CMK) tracking and Kalman filtering, to continuously update the location of moving objects. The proposed algorithm takes advantage of the structure from motion (SfM) to estimate the pose of moving camera, and then the estimated camera’s yaw angle is used as a feedback to improve the accuracy of the ground plane estimation. To further robustly and efficiently tracking objects under occlusion, the constrained multiple kernel tracking technique is adopted in the proposed system to track moving objects in 3D space (depth). The proposed system is evaluated on several challenging datasets, and the experimental results show the favorable performance, which not only can efficiently track on-road objects in a dashcam equipped on a free-moving vehicle but also can well handle occlusion in the tracking.
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CEKLJ, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Both spin-crossover complexes and molecular nanomagnets display bistable magnetic states, potentially behaving as elementary binary units for information storage. It is a challenge to introduce ...spin-crossover units into molecular nanomagnets to switch the bistable state of the nanomagnets through external stimuli-tuned spin crossover. Here we report an iron(II) spin-crossover unit and paramagnetic iron(III) ions that are incorporated into a well-isolated double-zigzag chain. The chain exhibits thermally induced reversible spin-crossover and light-induced excited spin-state trapping at the iron(II) sites. Single-chain magnet behaviour is actuated accompanying the synergy between light-induced excited spin-state trapping at the iron(II) sites and ferromagnetic interactions between the photoinduced high-spin iron(II) and low-spin iron(III) ions in the chain. The result provides a strategy to switch the bistable state of molecular nanomagnets using external stimuli such as light and heat, with the potential to erase and write information at a molecular level.
Long non-coding RNAs (lncRNAs) have been shown to contribute to progression and prognosis of hepatocellular carcinoma (HCC). However, expression profiling and interaction of lncRNAs with messenger ...RNAs (mRNAs) and microRNAs (miRNAs) remain largely unknown in HCC. The expression profiling of lncRNAs, mRNA and miRNAs was obtained using microarray. The Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analysis were used to characterize potential functions of differentially expressed mRNAs. Cytoscape was applied to construct an lncRNA-miRNA-mRNA co-expression network and candidate lncRNAs were validated via quantitative PCR in 30 pairs of HCC and adjacent tumor-free tissues. In this study, 1,056 upregulated and 1,288 downregulated lncRNAs were identified, while 2,687 mRNAs and 6 miRNAs were aberrantly expressed in HCC compared with adjacent tumor-free tissues. Potential functions of differentially expressed mRNAs were demonstrated to significantly participate in modulating critical genes in the cell cycle, such as cyclin E1 and cyclin B2. After screening, 95 lncRNAs, 5 miRNAs and 36 mRNAs were recruited for construction of lncRNA-mRNA-miRNA co-expression network in the cell cycle pathway. Subsequently, the top 5 lncRNAs that potentially modulate critical genes in the cell cycle were selected as the candidates for further verification. Kaplan-Meier curves using the Cancer Genome Atlas database showed that 13 targeted mRNAs were associated with overall survival of HCC patients. Finally, three lncRNAs, including ENST00000522221, lnc-HACE1-6:1 and lnc-ICOSLG-11:1, are significantly upregulated in HCC tissues compared with adjacent tumor-free tissues. These findings suggest that lncRNAs play essential roles in the pathogenesis of HCC via regulating coding genes and miRNAs, and may be important targets for diagnosis and treatment of this disease.
Chemically modified graphite is an economical material with promising applications in its own right or as an intermediate in the synthesis of graphene. However, because of its extreme chemical ...inertness, to date only two methods-oxidation and fluorination-have been found which can modify graphite with high yield and large throughput. Herein, we describe a third chemical approach for the synthesis of large quantities of highly modified graphite which uses a microwave-sparks-assisted halogenation reaction. The resulting graphite halide can easily be exfoliated into monolayer graphene in organic solvents. The structure and electronic properties of the original graphene can be recovered after thermal annealing of the graphene halide. Furthermore, the graphene halide can be further modified by a variety of organic functional groups. Solution-processed field-effect transistors based on the graphene halides resulted in device performances were comparable to, or even better than, that of graphene oxide.
The scenario of multi-sector SUSY breaking predicts pseudo-goldstinos which are not absorbed by the gravitino and their mass can be as low as O(0.1) GeV. Since the interactions of pseudo-goldstinos ...are not so weak as gravitino, a produced higgsino can decay to a pseudo-goldstino plus a Higgs boson insider the detector at the LHC, and thus the higgsino pair production can lead to the signal of Higgs pair plus missing energy. For the scenario of natural SUSY which requires rather light higgsinos, such events may sizably outnumber the Higgs pair events predicted by the SM and be accessible at the HL-LHC (14 TeV with a luminosity of 3 ab−1). In this work we examine the observability of such Higgs pair plus missing energy from the decay of light higgsinos produced at the HL-LHC. Considering three channels of the Higgs-pair decay (bbWW⁎, bbγγ, bbbb), our detailed Monte Carlo simulations for the signal and backgrounds show that the best channel is bbbb+/ET, whose statistical significance can reach 2σ level for a light higgsino allowed by current experiments. This is over the SM Higgs pair result which is about 1.8σ.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This paper presents a sliding-mode control (SMC) scheme via multiresonant sliding surface for single-phase grid-connected voltage source inverter with an LCL filter to eliminate the grid current ...tracking error as well as suppress its total harmonic distortion (THD). In general, the design of SMC leads to a sliding surface that is a linear combination of the system state variables and the generated references. The sliding surface would drift while the system parameters change or external disturbance exists, which affects the tracking error and THD of system output seriously. Moreover, for ac tracking system, integral SMC can reduce, but not fully alleviate the sinusoidal tracking error and has limited ability to suppress the grid current harmonics, especially for high-order harmonics. In order to fully eliminate the grid current tracking error and suppress its THD effectively, multiple resonant terms of the grid current error are added to the sliding function. It is used for the first time in the SMC. This method can be used for an arbitrary ac tracking system. Simulation and experimental results on a 5-kVA single-phase grid-connected inverter prototype show the effectiveness of the proposed control strategy. The tracking precision of the grid current is about 0.91% and the THD of the grid current is 0.76%.
This paper presents a systematic investigation on the incorporation of chemical exfoliation graphene sheets (GS) in TiO2 nanoparticle films via a molecular grafting method for dye-sensitized solar ...cells (DSSCs). By controlling the oxidation time in the chemical exfoliation process, both high conductivity of reduced GS and good attachment of TiO2 nanoparticles on the GS were achieved. Uniform GS/TiO2 composite films with large areas on conductive glass were prepared by electrophoretic deposition, and the incorporation of GS significantly improved the conductivity of the TiO2 nanoparticle film by more than 2 orders of magnitude. Moreover, the power conversion efficiency for DSSC based on GS/TiO2 composite films is more than 5 times higher than that based on TiO2 alone, indicating that the incorporation of GS is an efficient means for enhancing the photovoltaic (PV) performance. The better PV performance of GS/TiO2 DSSC is also attributed to the better dye loading of GS/TiO2 film than that of TiO2 film. The effect of GS content on the PV performances was also investigated. It was found that the power conversion efficiency increased first and then decreased with the increasing of GS concentration due to the decrease in the transmittance at high GS content. Further improvements can be expected by fully optimizing fabrication conditions and device configuration, such as increasing dye loading via thicker films. The present synthetic strategy is expected to lead to a family of composites with designed properties.
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IJS, KILJ, NUK, PNG, UL, UM
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