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Current situations,advantages/disadvantages and future developments of resilient deformation characterizations of unbound granular material:A state-of-the-art review

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Journal of Traffic and Transportation Engineering(English Edition) 2023年第6期10卷 964-1000页

作者： Shaohui Li peiwen Hao Key Laboratory of Road Structure and Material School of HighwayChang'an UniversityXi'an 710064China Key Laboratory of Road and Traffic Engineering of Ministry of Education Tongji UniversityShanghai 201804China

A state-of-the-art review was delivered in the manuscript to analyze the current situations and the advantages/disadvantages of resilient deformation related issues to the unbound granular material(UGM),including testing methods,influencing factors and constitutive models,through which the bottlenecks in UGM resilient deformation characterizations were located and new theories and future research recommendations were *** with other testing methods,the hollow cylinder test and true triaxial test are the only two to determine the anisotropic moduli of the *** significant advantages are observed in more advanced test apparatus such as true triaxial test,further improvements should be made,such as more advanced process identification control algorithm,to more conveniently control the nine independent hydraulic system and accurately measure UGM anisotropic *** and conflicts in understanding the influencing factors to UGM resilient modulus were located,such as the stress history,the residual stress,the dry density,the gradation/fine content and the freeze-thaw cycle,based on which future research could be *** reviewing evolutions of the UGM constitutive models and comparing their representativeness and complexity comprehensively,major drawbacks were discovered and a new theory was proposed afterward to modify the UGM constitutive model,although further validations are still needed.

关键词： Unbound granular material Resilient characterization Testing method Influencing factor Constitutive model

Preparation of hydrogels with uniform and gradient chemical structures using dialdehyde cellulose and diamine by aerating ammonia gas

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Frontiers of Chemical Science and Engineering 2018年第3期12卷 383-389页

作者： peiwen Liu Carsten Mai Kai Zhang Wood Technology and Wood Chemistry Georg-August-Universitat Gottingen 37077 Gottingen Germany Wood Biology and Wood Products Georg-August-Universitat Gottingen 37077 Gottingen Germany

Hydrogels with precisely designed structures represent promising materials with a broad application spectrum, such as for sensor, tissue engineering and biomimetic technology. However, with highly reactive compounds, the preparation of hydrogels still needs an efficient approach for desired distribution of each component within hydrogels. In addition, a method for in situ preparation of gradient hydrogels is still lacking. Herein, we report the formation ofhydrogels with either uniform or gradient internal structures via a novel, simple but very efficient method by aerating ammonia gas （NH3 gas） into the solution of dialdehyde cellulose （DAC） and a diamine. As-prepared hydrogels exhibited uniform microscopic and chemical structure or gradient distribution Of functional groups. Due to lots of aldehyde groups on DAC chains, functional hydrogels can be prepared by using diverse diamines. For instance, hydrogels prepared by using 1,6-hexanediamine as a cross-linker were responsive to pH values. Moreover, this controllable process of aerating NH3 gas allows the in situ formation of gradient hydrogels; for instance, by using cyanamide as a reaction counterpart, gradient hydrogels with gradient distributions of cyanide groups were prepared.

关键词： hydrogel uniform gradient dialdehyde cellulose ammonia gas diamine

Radar false alarm plots elimination based on multi-feature extraction and classification

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The Journal of China Universities of Posts and Telecommunications 2024年第1期31卷 83-92页

作者： Cheng Yi Zhao Yan Yin peiwen School of Control Science and Engineering Tiangong UniversityTianjin 300387China Tianjin Key Laboratory of Intelligent Control of Electrical Equipment Tianjin 300387China

Caused by the environment clutter,the radar false alarm plots are *** false alarm points has always been a key issue in Radar plots *** this paper,a radar false alarm plots elimination method based on multi-feature extraction and classification is proposed to effectively eliminate false alarm ***,the density based spatial clustering of applications with noise(DBSCAN)algorithm is used to cluster the radar echo data processed by constant false-alarm rate(CFAR).The multi-features including the scale features,time domain features and transform domain features are ***,a feature evaluation method combining pearson correlation coefficient(PCC)and entropy weight method(EWM)is proposed to evaluate interrelation among features,effective feature combination sets are selected as inputs of the ***,False alarm plots classified as clutters are *** experimental results show that proposed method can eliminate about 90%false alarm plots with less target loss rate.

关键词： radar plots elimination density based spatial clustering of applications with noise multi-feature extraction classifier

The Influence of Material Related Parameters on the Mechanical Properties of Foamed Asphalt Mix

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Journal of Wuhan University of Technology(Materials Science) 2014年第1期29卷 119-125页

作者：徐金枝 HAO peiwen Key Laboratory for Road Structure and Material of Ministry of Communications Chang'an University

By indirect tensile strength （ITS） test and unconfined compressive strength （UCS） test, the influence of various material related parameters, including asphalt foamability, aggregate temperature, mixing moisture content （MMC） and foamed asphalt （FA） content, on the mechanical properties of FA mixes was studied. The results indicated that both asphalt foamability and aggregate temperature greatly affected ITS of FA mixes. Too low aggregate temperature was unfavorable for mechanical properties of FA mixes. Foamed index alone was unfit for the evaluation of asphalt foamability. Compared with half-life, expansion ratio had more prominent influence on ITS of FA mixes. MMC had significant impact on the mechanical properties of FA mixes and should be optimized by trial and test in FA mix design. The mechanical properties of FA mix were sensitive to the change of FA content. Compared with the ITS determined with standard Marshall specimens, both the ITS and UCS determined with static compressed specimens by 15 cm diameter were more effective in terms of choosing the optimal asphalt content for FA mixes.

关键词： road engineering foamed asphalt mix asphalt foamability aggregate temperature mixingmoisture content foamed asphalt content

The radial self-positioning algorithm of intelligent ultrasonic probe array in oil/gas pipeline

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High Technology Letters 2007年第4期13卷 379-382页

作者：宋寿鹏 Que peiwen Institute of Automatic Detection Shanghai Jiaotong University Shanghai 200030 P.R. China

The working principle of the pipeline intelligent pig and the structure of ultrasonic probe array used to detect defects in oil/gas pipeline are introduced. The effects of the array＇ s radial position in pipe on defect resolution are analyzed. The causes leading to radial positioning error are investigated. An algo- rithm for the radial self-positioning is presented. The experimental results show that the radial self-positioning algorithm can eliminate the array＇ s space position error effectively and improve the defect resolution.

关键词： intelligent ultrasonic probe array defect self-positioning algorithm pipeline

Ultrasonic flaw detection using EMD-based signal processing

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High Technology Letters 2006年第1期12卷 14-17页

作者：毛义梅 Que peiwen Institute of Automatic Detection Shanghai Jiaotong University Shanghai 200030 P.R. China

The precise detection of flaw echoes buried in backscattefing noise caused by material microstructure is a problem of great importance in uhrasonic non-destructive testing （NDT）. In this work, empirical mode decomposition （EMD） is proposed to deal with ultrasonic signal. A time-frequency filtering method based on EMD is designed to suppress noise and enhance flaw signals. Simulated results are presented, showing that the proposed method has an excellent performance even for a very low signal-to-noise ratio （SNR）. The improvement in flaw detection was experimentally verified using stainless steel pipe sample with artificial flaws.

关键词： empirical mode decomposition ultrasonic NDT time-frequency filtering

Interaction of Ca^(2+) and soil humic acid characterized by a joint experimental platform of potentiometric titration, UV–visible spectroscopy, and fluorescence spectroscopy

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Acta Geochimica 2021年第3期40卷 300-311页

作者： Haiming Tang Baohua Xiao peiwen Xiao State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of SciencesGuiyang 550081GuizhouChina University of Chinese Academy of Sciences Beijing 100049China

Rocky desertification has become a major environmental issue in the karst region of southwestern *** rocky desertification was more severe in regions of limestone soil than in adjacent regions of other soils,despite the relatively higher soil organic matter(SOM)content in limestone *** underlying mechanism remains *** speculated that the geochemical characteristics of limestone soils in the karst region plays an essential role,especially the high calcium content of limestone *** test this hypothesis,we collected limestone soil samples from a limestone soil profile in the southwestern China karst region and extracted humic acid(HA)from these limestone soil *** investigated the interaction of Ca^(2+)and three HA samples on a joint experimental platform,which consists of an automatic potentiometric titrator,a UV–visible spectrometer,and a Fluorescence *** solutions were titrated by Ca^(2+)and optical spectra of the HA solutions were monitored during the titration *** results indicated that:(1)the interaction of Ca^(2+)and HA is a combined process of adsorption and *** dominated the overall distribution behavior of Ca^(2+),which could be fit by Langmuir and Freundlich isotherm *** was distinguished only when the concentration of Ca2+is low;(2)the changes of UV–visible spectroscopy and excitation–emission matrix fluorescencespectroscopy spectra of HA samples when they were binding with Ca^(2+)implied the apparent molecular size and structure of HA became larger and more complex;(3)the combination of Ca^(2+)and HA plays an important role in the SOM preservation of limestone soils but the stability of the Ca–HA association was relatively *** present study draws attention to maintaining the relatively higher Ca^(2+)concentration in limestone soils in ecologic restoration attempts in karst regions.

关键词： Limestone soil Humic acid Calcium Interaction Titration UV–Vis EEM

Target recognition based on modified combination rule

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Journal of Systems Engineering and Electronics 2006年第2期17卷 279-283页

作者： Chen Tianlu Que peiwen Inst. of Automatic Detection Shanghai Jiaotong Univ. Shanghai 200030 China

Evidence theory is widely used in the field of target recognition. The invalidation problem of this theory when dealing with highly conflict evidences is a research hotspot. Several alternatives of the combination rule are analyzed and compared. A new combination approach is proposed. Calculate the reliabilities of evidence sources using existing evidences. Construct reliabilities judge matrixes and get the weights of each evidence source. Weight average all inputted evidences. Combine processed evidences with D-S combination rule repeatedly to identify a target. The application in multi-sensor target reeognition as well as the comparison with typical alternatives all validated that this approach can dispose highly conflict evidences efficiently and get reasonable reeognition results rapidly.

关键词： evidence theory combination rule conflict evidences target recognition data fusion.

Simplified dark matter models with loop effects in direct detection and the constraints from indirect detection and collider search

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Chinese Physics C 2019年第11期43卷 21-29页

作者： Tong Li peiwen Wu School of Physics Nankai UniversityTianjin 300071China School of Physics KIAS85 HoegiroSeoul 02455Republic of Korea

We reexamine the simplified dark matter(DM) models with fermionic DM particle and spin-0 *** DM-nucleon scattering cross sections in these models are low-momentum suppressed at tree-level,but receive sizable loop-induced spin-independent *** perform one-loop calculations for scalar-type and twist-2 DM-quark operators,and complete two-loop calculations for scalar-type DM-gluon *** the looplevel contribution from new operators,we find that future direct detection experiments could be sensitive to a fraction of the parameter *** indirect detection and collider search also provide complementary constraints on these models.

关键词： direct dark matter detection loop effect simplified dark matter models