Research on Adaptive SVR Indoor Location Based on GA Optimization

Wireless Personal Communications - Indoor positioning based on the received signal strength index of ZigBee has received more and more attention due to its low cost, low hardware power consumption...     

On Mixed Pressure-Velocity Regularity Criteria to the Navier-stokes Equations in Lorentz Spaces,Part Ⅱ:The Non-slip Boundary Value Problem

This paper is a continuation of the authors recent work [Beir?o da Veiga, H.and Yang, J., On mixed pressure-velocity regularity criteria to the Navier-Stokes equations in Lorentz spaces, Chin. Ann. Math., 42(1), 2021, 1–16], in which mixed pressure-velocity criteria in Lorentz spaces for Leray-Hopf weak solutions of the three-dimensional NavierStokes equations, in the whole space R~3 and in the periodic torus T~3, are established. The purpose of the present work is to extend the result of mentio...     

Amperometric nitrite sensor based on free-standing carbon nanotube/methylene blue composite paper

Ionics - Free-standing paper-like electrochemical sensors have many advantages such as high flexibility, thickness adjustability, and large electroactive surface area, when compared to traditional...     

Background subtraction based on circulant matrix

Detecting moving objects in a scene is a fundamental and critical step for many high-level computer vision tasks. However, background subtraction modeling is still an open and challenge problem, particularly in practical scenarios with drastic illumination changes and dynamic backgrounds. In this paper, we present a novel background modeling method focused on dealing with complex environments based on circular shift operator. The background model is constructed by performing circular shifts on the neighborhood of each pixel, which forms a basic region unit. The foreground mask is obtained via two stages. The first stage is to subtract the established background from the current frame to obtain the distance map. The second is to adopt the graph cut on the distance map. In order to adapt to the background changes, the background model is updated with an adaptive update rate. Experimental results on indoor and outdoor videos demonstrate the efficiency of our proposed method.     

Applicability of Hadamard relaxation method to MMW and THz Imaging with compressive sensing

Compressive sensing (CS) is widely considered a promising method for millimeter wave (MMW) and terahertz (THz) imaging, especially in security screening. In many real-life application scenarios, a CS reconstruction algorithm has to be simultaneously robust, noise-tolerant and fast to be of practical use. However, a lot of CS reconstruction algorithms are not designed aiming at such overall performance, preventing them to become applicable in commercial imaging systems. Having investigated some CS algorithms, we find that Hadamard relaxation method is a potential candidate for commercial CS imaging. By using MATLAB, we study Hadamard relaxation method focusing on its under-sampling ratio, tolerance to noise and efficiency. Comparisons with several other CS algorithms are made using the available data in references. The results demonstrate that the overall performance of Hadamard relaxation method is among the best for real-life and real-time applications of MMW and THz imaging.     

Synthesis,Crystal Structure,and Diastereomeric Transfer of Pentacoordinated Phosphoranes Containing Valine or Iso-Leucine Residue

Pentacoordinated phosphoranes containing valine or iso-leucine residue (2-phenyl-2,7⁵-spiro[1,3,2-phenanthrodioxaphosphole-2,2′-1,3,2-oxazaphospholan]-5′-one) were synthesized through sequential two-step reactions, whereby the reaction products of phenyldichlorophosphine with N,O-bis(trimethylsilyl)valine or iso-leucine were followed by the addition of phenanthrenequione, and the crystals of 4a and 4b were obtained from benzene and hexane mixed solution. The x-ray structure of the crystals 4a and 4b revealed that they are distorted TBP, exhibiting R_P absolute configuration. The ³¹P NMR spectra showed that the S_P diastereomer could transfer into the other one R_P that came out from the solution during crystallization. Correspondingly, when it was dissolved in solvents the R_P diastereomer transferred into the other one S_P, and the pair of diastereomers changed each other in solution at room temperature through a phosphonium carboxylate zwitterions intermediate.

     

退火温度对La_(0.4)Nd_(0.1)Sr_(0.5)MnO_3薄膜结构及CMR的影响

利用射频磁控溅射法结合后退火工艺在LaAlO3(100)衬底上制备了La0.4Nd0.1Sr0.5MnO3(LNSMO)一系列薄膜样品。通过X射线衍射仪(XRD)、原子力显微镜(AFM)、光电子能谱(XPS)、四探针法对其结构及性质进行了测试。结果表明,薄膜在700～900℃温度区间退火形成单相的赝立方钙钛矿结构。退火温度不同导致薄膜中氧含量发生变化并且对晶粒的尺寸也有很大影响。经过850℃退火的薄膜样品,在室温300 K,磁场为1.5 T的条件下,磁电阻达到24.9%。     

A general approach to determining the evolution of molecular weight distribution curves of linear polymers undergoing chain scission

A numerical method is developed to compute the development of molecular weight distribution (MWD) curves of linear polymers undergoing chain scission. The method can be applied to complex chain scission kinetics and for arbitrarily complex initial MWD curves. Our method is based on the method of lines (MoL). Different from the existing numerical scheme, we propose the use of logarithmically spaced points. This development ensures the accuracy of the computed MWD curves at low molecular weights, and it does not require a very fine discretization to produce an accurate result.