Spin-orbit tuned metal-insulator transitions in single-crystal Sr2Ir1-xRhxO4 (0\leqx\leq1)

Sr2IrO4 is a magnetic insulator driven by spin-orbit interaction (SOI) whereas the isoelectronic and isostructural Sr2RhO4 is a paramagnetic metal. The contrasting ground states have been shown to result from the critical role of the strong SOI in the iridate. Our investigation of structural, transport, magnetic and thermal properties reveals that substituting 4d Rh4+ (4d5) ions for 5d Ir4+(5d5) ions in Sr2IrO4 directly reduces the SOI and rebalances the competing energies so profoundly that it generates a rich phase diagram for Sr2Ir1-xRhxO4 featuring two major effects: (1) Light Rh doping (0\leqx\leq0.16) prompts a simultaneous and precipitous drop in both the electrical resistivity and the magnetic ordering temperature TC, which is suppressed to zero at x = 0.16 from 240 K at x=0. (2) However, with heavier Rh doping (0.24< x<0.85 (\pm0.05)) disorder scattering leads to localized states and a return to an insulating state with spin frustration and exotic magnetic behavior that only disappears near x=1. The intricacy of Sr2Ir1-xRhxO4 is further highlighted by comparison with Sr2Ir1-xRuxO4 where Ru4+(4d4) drives a direct crossover from the insulating to metallic states.Comment: 5 figure

Proteomics analysis of differentially expressed proteins in chicken trachea and kidney after infection with the highly virulent and attenuated coronavirus infectious bronchitis virus in vivo

<p>Abstract</p> <p>Background</p> <p>Infectious bronchitis virus (IBV) is first to be discovered coronavirus which is probably endemic in all regions with intensive impact on poultry production. In this study, we used two-dimensional gel electrophoresis (2-DE) and two-dimensional fluorescence difference gel electrophoresis (2-DIGE), coupled with matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI-TOF/TOF-MS), to explore the global proteome profiles of trachea and kidney tissues from chicken at different stages infected <it>in vivo </it>with the highly virulent ck/CH/LDL/97I P₅strain of infectious bronchitis virus (IBV) and the embryo-passaged, attenuated ck/CH/LDL/97I P₁₁₅strain.</p> <p>Results</p> <p>Fifty-eight differentially expressed proteins were identified. Results demonstrated that some proteins which had functions in cytoskeleton organization, anti-oxidative stress, and stress response, showed different change patterns in abundance from chicken infected with the highly virulent ck/CH/LDL/97I P₅strain and those given the embryo-passaged, attenuated P₁₁₅stain. In addition, the dynamic transcriptional alterations of 12 selected proteins were analyzed by the real-time RT-PCR, and western blot analysis confirmed the change in abundance of heat shock proteins (HSP) beta-1, annexin A2, and annexin A5.</p> <p>Conclusions</p> <p>The proteomic alterations described here may suggest that these changes to protein expression correlate with IBV virus' virulence in chicken, hence provides valuable insights into the interactions of IBV with its host and may also assist with investigations of the pathogenesis of IBV and other coronavirus infections.</p

Kinect-Based Vision System of Mine Rescue Robot for Low Illuminous Environment

This paper presents Kinect-based vision system of mine rescue robot working in illuminous underground environment. The somatosensory system of Kinect is used to realize the hand gesture recognition involving static hand gesture and action. A K-curvature based convex detection method is proposed to fit the hand contour with polygon. In addition, the hand action is completed by using the NiTE library with the framework of hand gesture recognition. In addition, the proposed method is compared with BP neural network and template matching. Furthermore, taking advantage of the information of the depth map, the interface of hand gesture recognition is established for human machine interaction of rescue robot. Experimental results verify the effectiveness of Kinect-based vision system as a feasible and alternative technology for HMI of mine rescue robot

An image dust removal and enhancement method in low illumination environment based on dark-bright channel segmentation and fusion

Due to the influence of dust, water mist and low illumination environment in coal mine, it is very difficult to accurately identify the monitoring images of belt transportation system. Aiming at the problem of poor image processing results and efficiency of existing dust and fog removal methods, a dust and fog removal and enhancement method for low-illumination environment images based on dark-bright channel segmentation and fusion is proposed. Firstly, the channel difference is corrected by threshold segmentation combined with gamma transform to solve the problem that the difference of pixel values between the regions with large dust and fog concentration and other regions is not obvious due to the influence of low illumination environment. After correction, the global atmospheric light intensity which is more in line with the actual situation is obtained by guiding the original image to do guided filtering. Then, in order to solve the problem that the dark channel prior fails in the area with large dust concentration, the bright channel prior is introduced to supplement, and the channel component is used to assist the fusion of dark channel and bright channel transmittance, so as to avoid the problem of edge pixel attribution caused by multiple segmentation. Finally, the RGB image after dehazing is transferred to HSV space, the brightness component is histogram equalized and the brightness component before and after equalization is weighted and fused. The objective index evaluation is used to select the optimal aggregation weight for aggregation. At the same time, considering the saturation loss in the dehazing process and the correlation between the brightness component and the saturation component, the saturation adaptive correction function is proposed to correct the image saturation and keep the tone component unchanged. Then the image is transferred back to RGB space to obtain an image with moderate brightness, rich information retention and bright color. In order to verify the effectiveness of the proposed method, subjective vision, objective indicators, and target detection accuracy and confidence are used to compare the algorithms. The experimental results show that the proposed method is superior to the comparison algorithm in the above four indicators, and the image details are retained more abundant and the visual perception is better

Pick-and-place trajectory tracking control for cable-driven gangue sorting robots

The cable-driven parallel robots have the advantages of fast moving speed, large workspace and strong dynamic load carrying capacity, so they are employed to perform the pick-and-place operation of the target gangues quickly and accurately. However, due to the flexibility and the unidirectional characteristics of the cables, the cables must be kept in tension all the time, which makes the control of the robots face great challenges. At the same time, the dynamic impact, uncertainty of dynamic parameters, external interference and other factors caused by the process of the pick-and-place the target gangues will inevitably affect the motion accuracy of the end-grab of the robot, and even lead to the failure of the sorting of target gangues. Therefore, a robust adaptive fuzzy control strategy, which can ensure the motion accuracy of the end-grab of the cable-driven gangue sorting robots, is presented to overcome the disturbances of dynamic parameters and the influences of external interference in the process of picking and placing the gangues. Based on Lyapunov stability theory, the stability of the proposed control strategy is proved. The simulation analysis of the proposed control strategy is carried out through a spatial spiral trajectory and practical pick-and-place trajectory for the robot. The results show that the end-grab of the robot has a good tracking effect on the predetermined trajectory, and the maximum position tracking error and root mean square error are 2×10−2 m and 8.9867×10−4 m, respectively; and furthermore, the cable tensions are smooth and continuous, which satisfies the constraint conditions of the cable tensions. It is proved that the proposed robust adaptive fuzzy control strategy in this paper is effective and reliable for the trajectory tracking control of the cable-driven gangue sorting robots. This study can lay a good theoretical foundation for the further application of the cable-driven gangue sorting robots

Honeycomb lattice Na2IrO3 at high pressures: A robust spin-orbit Mott insulator

The honeycomb iridate Na2IrO3 has received much attention as a candidate to realize a quantum spin liquid state, but the nature of its insulating state remains controversial. We found that the material exhibits structural transitions at 3 and 10 GPa. The former is accompanied by 166-meV suppression of the activation gap, but the energies for the low-lying interband transitions change by less than 10 meV. This can be reconciled in a picture in which the application of high pressure barely shifts the electronic bands, but rather merely broadens them. First-principles calculations uncover a strong correlation between the band gap and the β angle of the monoclinic structure, indicating non-negligible interlayer coupling. These results offer clear evidence for a spin-orbit Mott insulating state in Na2IrO3 and are inconsistent with the quasimolecular orbital model