This paper proposes a new and distribution-free test called "Group Contingency" test (GC, for short) for testing two or several independent samples. Compared with traditional nonparametric tests, GC test tends to ...
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This paper proposes a new and distribution-free test called "Group Contingency" test (GC, for short) for testing two or several independent samples. Compared with traditional nonparametric tests, GC test tends to explore more information based on samples, and it's location-, scale-, and shapesensitive. The authors conduct some simulation studies comparing GC test with Wilcoxon rank sum test (W), Kolmogorov-Smirnov test (KS) and Wald-Wolfowitz runs test (WW) for two sample case, and with Kruskal-Wallis (KW) for testing several samples. Simulation results reveal that GC test usually outperforms other methods.
The utilization of eco-friendly,lightweight,high-efficiency and high-absorbing electromagnetic interference(EMI)shielding composites is imperative in light of the worldwide promotion of sustainable *** this work,magne...
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The utilization of eco-friendly,lightweight,high-efficiency and high-absorbing electromagnetic interference(EMI)shielding composites is imperative in light of the worldwide promotion of sustainable *** this work,magnetic poly(butyleneadipate-coterephthalate)(PBAT)microspheres were firstly synthesized via phase separation method,then PBAT composite foams with layered structure was constructed through the supercritical carbon dioxide foaming and scraping *** merits of integrating ferroferric oxideloaded multi-walled carbon nanotubes(Fe3O4@MWCNTs)nanoparticles,a microcellular framework,and a highly conductive silver layer have been judiciously orchestrated within this distinctive layered *** are consumed throughout the process of“absorption-reflection-reabsorption”as much as possible,which greatly declines the secondary radiation *** biodegradable PBAT composite foams achieved an EMI shielding effectiveness of up to 68 dB and an absorptivity of 77%,and authenticated favorable stabilization after the tape adhesion experiment.
A series of polypropylene(PP)/poly(ethylene-co-propylene) in-reactor alloys with different ethylene contents was prepared through a two-stage polymerization process using a MgCl2/TiCl4/diisobutyl phthalate/phospha...
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A series of polypropylene(PP)/poly(ethylene-co-propylene) in-reactor alloys with different ethylene contents was prepared through a two-stage polymerization process using a MgCl2/TiCl4/diisobutyl phthalate/phosphate tris-methylphenyl ester catalyst system. The ethylene content, particle shape, fractured surface, and glass-transition temperature(Tg) of the obtained PP in-reactor alloys were characterized by means of nuclear magnetic resonance, scanning electron microscopy(SEM), and dynamic mechamcal analysis(DMA). The ethylene content of the PP alloys increased from 2.34% to 26.69% when the propylene/ethylene feed ratio was increased from 66/34 to 54/46(molar ratio). Morevoer, the increment in ethylene content increased the notched Izod impact strength of the resulting PP alloys. The impact strength of the PP alloy with an ethylene content of 26.69% was 55.8 kJ/m^2, which is 12.7 times that of isotactic polypropylene. The results of DMA and SEM analysis reveal that ethylene-propylene random copolymer(EPR) in the PP alloy has a low Tg of ca. -50℃ and a high interface compatibility with the PP matrix. The excellent impact performance of the PP alloy can be attributed to the uniform dispersal of EPR in the alloy particles and PP matrix.
Positioning and mapping technology is a difficult and hot topic in autonomous driving environment sensing *** a complex traffic environment,the signal of the Global Navigation Satellite System(GNSS)will be blocked,lea...
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Positioning and mapping technology is a difficult and hot topic in autonomous driving environment sensing *** a complex traffic environment,the signal of the Global Navigation Satellite System(GNSS)will be blocked,leading to inaccurate vehicle *** ensure the security of automatic electric campus vehicles,this study is based on the Lightweight and Ground-Optimized Lidar Odometry and Mapping on Variable Terrain(LEGO-LOAM)algorithm with a monocular vision system *** algorithm framework based on Lidar-IMU-Camera(Lidar means light detection and ranging)fusion was proposed.A lightweight monocular vision odometer model was used,and the LEGO-LOAM system was employed to initialize monocular *** visual odometer information was taken as the initial value of the laser *** the back-end opti9mization phase error state,the Kalman filtering fusion algorithm was employed to fuse the visual odometer and LEGO-LOAM system for *** visual word bag model was applied to perform loopback *** the test results into account,the laser radar loopback detection was further optimized,reducing the accumulated positioning *** real car experiment results showed that our algorithm could improve the mapping quality and positioning accuracy in the campus *** Lidar-IMU-Camera algorithm framework was verified on the Hong Kong city dataset *** with the LEGO-LOAM algorithm,the results show that the proposed algorithm can effectively reduce map drift,improve map resolution,and output more accurate driving trajectory information.
The hot deformation behavior of an ultralow-carbon microalloyed steel was investigated using an MMS-200 thermal simulation test machine in a temperature range of 1073-1373 K and strain rate range of 0.01-10 *** result...
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The hot deformation behavior of an ultralow-carbon microalloyed steel was investigated using an MMS-200 thermal simulation test machine in a temperature range of 1073-1373 K and strain rate range of 0.01-10 *** results show that the flow stress decreases with increasing deformation temperature or decreasing strain *** strain-compensated constitutive model based on the Arrhenius equation for this steel was established using the true stress-strain data obtained from a hot compression ***,a new constitutive model based on the Z-parameter was proposed for this *** predictive ability of two constitutive models was compared with statistical *** results indicate the new constitutive model based on the Z-parameter can more accurately predict the flow stress of an ultralow-carbon microalloyed steel during hot *** dynamic recrystallization(DRX)nucleation mechanism at different deformation temperatures was observed and analyzed by transmission electron microscopy(TEM),and strain-induced grain boundary migration was observed at 1373 K/0.01 s^-1.
We report a facile coagglomeration method for preparing graphene (G)/MgCl2‐supported Ti‐based Ziegler‐Natta catalysts. The effects of graphene feed ratio on catalyst morphology and ethylene polymerization behavior ...
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We report a facile coagglomeration method for preparing graphene (G)/MgCl2‐supported Ti‐based Ziegler‐Natta catalysts. The effects of graphene feed ratio on catalyst morphology and ethylene polymerization behavior were examined. The synthesized catalyst exhibited very high activity for ethylene polymerization. The resultant polyethylene (PE)/G nanocomposites showed a layered morphology, and the graphene fillers were well dispersed in the PE matrix. In addition, the thermal stability and mechanical properties of PE were significantly enhanced with the introduction of a very small amount of G fillers (0.05 wt%). This work provides a facile approach to the production o fhigh‐performance PE.
Traffic sign detection in real scenarios is challenging due to their complexity and small size,often preventing existing deep learning models from achieving both high accuracy and real-time *** improved YOLOv8 model f...
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Traffic sign detection in real scenarios is challenging due to their complexity and small size,often preventing existing deep learning models from achieving both high accuracy and real-time *** improved YOLOv8 model for traffic sign detection is ***,by adding Coordinate Attention(CA)to the Backbone,the model gains location information,improving detection ***,we also introduce EIoU to the localization function to address the ambiguity in aspect ratio descriptions by calculating the width-height difference based on ***,Focal Loss is incorporated to balance sample difficulty,enhancing regression ***,the model,YOLOv8-CE(YOLOv8-Coordinate Attention-EIoU),is tested on the Jetson Nano,achieving real-time street scene detection and outperforming the Raspberry Pi *** results show that YOLOv8-CE excels in various complex scenarios,improving mAP by 2.8%over the original *** model size and computational effort remain similar,with the Jetson Nano achieving an inference time of 96 ms,significantly faster than the Raspberry Pi 4B.
There are lots of theories about the causation of ground fissures in Xi’an,such as the tectonics theory,the excessive groundwater exploitation theory and the compositive theory. Based on the construction of the geolo...
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There are lots of theories about the causation of ground fissures in Xi’an,such as the tectonics theory,the excessive groundwater exploitation theory and the compositive theory. Based on the construction of the geologic environment monitoring network in Guanzhong urban agglomeration,the latest survey of ground fissures and land subsidence in Yuhuazhai in Xi’an shows that the extensive piping and quicksand in self-supply wells is a factor to induce ground fissures and land subsidence. It is suggested that the seepage deformation caused by high hydraulic gradient leads to sand gushing and changes some aquifers into the composite aquifer,which is the main factor to induce ground fissures and land subsidence. The development characteristics of ground fissures and land subsidence caused by seepage deformation were summarized. The results will supply new schemes and methods for the causation of land subsidence and ground fissures in Xi’an and lay out a clear road map of measures to control land subsidence and ground fissures.
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