Calcined ginger nuts admixed by fly ash and quartz sand(CGN-(F+S))has been validated to be basically compatible to earthen sites as an anchor grout.Accelerated ageing tests including water stability test,temperature a...Calcined ginger nuts admixed by fly ash and quartz sand(CGN-(F+S))has been validated to be basically compatible to earthen sites as an anchor grout.Accelerated ageing tests including water stability test,temperature and humidity cycling test,soundness test and alkali resistance test are conducted with the objective to further research the property changes of CGN-(F+S)grout.Density,surface hardness,water penetration capacity,water permeability capacity,soluble salt,scanning electron microscopy(SEM)images and energy dispersive spectrometry(EDS)spectrum of these samples have been tested after accelerated ageing tests.The results show that densities of samples decrease,surface hardness,water penetration capacity and water permeability capacity of samples increase generally.Besides,soluble salt analysis,SEM and EDS results well corroborate the changes.Based on the results it can be concluded that property changes are most serious after temperature and humidity cycling test,followed by water stability,soundness and alkali resistance test in sequence.But in general,CGN-(F+S)still has good durability.展开更多
An outdoor aging test base for geosynthetics was established in Wuhan,central China to investigate the long-term aging performance of geosynthetics. Outdoor photo-oxygen aging tests for high density polyethylene(HDPE)...An outdoor aging test base for geosynthetics was established in Wuhan,central China to investigate the long-term aging performance of geosynthetics. Outdoor photo-oxygen aging tests for high density polyethylene(HDPE) geogrid have been carried out in the base. Test results show that in the initial nine months,the tensile strength of geogrid remains unchanged or even gets larger,while the corresponding strain at break decreases slightly,exhibiting hard and brittle trend due to secondary compensatory responses to the ultraviolet(UV) aging: UV provides the required chemical crosslinking energy,resulting in the polymer crosslinking reaction. Tensile strength of the geogrid increases by about 5% in the initial nine months,but decreases after the initial nine months. The long-term research results at the test base could provide first-hand data for researching the aging properties of HDPE geogrid.展开更多
Detrital white mica single\|crystal Ar\|Ar ages from the Himalayan foreland sedimentary record are potentially a powerful tool in constraining source regions, tectonic evolution, and the timing and extent of exhumatio...Detrital white mica single\|crystal Ar\|Ar ages from the Himalayan foreland sedimentary record are potentially a powerful tool in constraining source regions, tectonic evolution, and the timing and extent of exhumation (Copeland 1990, Najman 1997, White 1999). However such studies require large numbers of analyses, and Ar/Ar total\|fusion of white mica grains is a very rapid and cost\|effective technique.Such analyses, however, do result in the sacrifice of internal consistency checks inherent in, for example, Ar/Ar step\|heating analysis.展开更多
整流器作为电能变换功率模块的关键环节,广泛应用于变频器等供电系统设备中,其运行可靠性直接影响整个系统的运行状态。为提高整流器运行可靠性,需针对其中的敏感部件整流二极管进行寿命预测,提出一种由改进后的灰狼优化算法(grey wolf ...整流器作为电能变换功率模块的关键环节,广泛应用于变频器等供电系统设备中,其运行可靠性直接影响整个系统的运行状态。为提高整流器运行可靠性,需针对其中的敏感部件整流二极管进行寿命预测,提出一种由改进后的灰狼优化算法(grey wolf optimization,GWO)优化简单循环单元(simple recurrent unit,SRU)网络超参数的预测模型。首先对二极管进行功率循环加速老化试验,对其特征参数进行分析,选取正向导通压降作为主要老化特征,其次采用改良策略后的GWO对SRU网络的学习率、隐藏层个数、迭代次数等超参数进行寻优,建立组合预测模型,最后将老化试验所得数据输入模型中进行训练以及验证,得到预测结果与其他模型对比。结果表明:本文模型具有更高的准确性,基于数据驱动的预测方法较传统分析建模方法提高了二极管寿命预测精度,进而提高了整流器工作可靠性。展开更多
基金Project(51578272)supported by the National Natural Science Foundation of China
文摘Calcined ginger nuts admixed by fly ash and quartz sand(CGN-(F+S))has been validated to be basically compatible to earthen sites as an anchor grout.Accelerated ageing tests including water stability test,temperature and humidity cycling test,soundness test and alkali resistance test are conducted with the objective to further research the property changes of CGN-(F+S)grout.Density,surface hardness,water penetration capacity,water permeability capacity,soluble salt,scanning electron microscopy(SEM)images and energy dispersive spectrometry(EDS)spectrum of these samples have been tested after accelerated ageing tests.The results show that densities of samples decrease,surface hardness,water penetration capacity and water permeability capacity of samples increase generally.Besides,soluble salt analysis,SEM and EDS results well corroborate the changes.Based on the results it can be concluded that property changes are most serious after temperature and humidity cycling test,followed by water stability,soundness and alkali resistance test in sequence.But in general,CGN-(F+S)still has good durability.
基金National Key R&D Program of China(2017YFC1501201)National Natural Science Foundation of China(51709017)Fundamental Research Fund for Central Research Institute(CKSF2014060/YT,CKSF2017009/YT,CKSF2017012/YT,CKSF2017022/YT)
文摘An outdoor aging test base for geosynthetics was established in Wuhan,central China to investigate the long-term aging performance of geosynthetics. Outdoor photo-oxygen aging tests for high density polyethylene(HDPE) geogrid have been carried out in the base. Test results show that in the initial nine months,the tensile strength of geogrid remains unchanged or even gets larger,while the corresponding strain at break decreases slightly,exhibiting hard and brittle trend due to secondary compensatory responses to the ultraviolet(UV) aging: UV provides the required chemical crosslinking energy,resulting in the polymer crosslinking reaction. Tensile strength of the geogrid increases by about 5% in the initial nine months,but decreases after the initial nine months. The long-term research results at the test base could provide first-hand data for researching the aging properties of HDPE geogrid.
文摘Detrital white mica single\|crystal Ar\|Ar ages from the Himalayan foreland sedimentary record are potentially a powerful tool in constraining source regions, tectonic evolution, and the timing and extent of exhumation (Copeland 1990, Najman 1997, White 1999). However such studies require large numbers of analyses, and Ar/Ar total\|fusion of white mica grains is a very rapid and cost\|effective technique.Such analyses, however, do result in the sacrifice of internal consistency checks inherent in, for example, Ar/Ar step\|heating analysis.
文摘整流器作为电能变换功率模块的关键环节,广泛应用于变频器等供电系统设备中,其运行可靠性直接影响整个系统的运行状态。为提高整流器运行可靠性,需针对其中的敏感部件整流二极管进行寿命预测,提出一种由改进后的灰狼优化算法(grey wolf optimization,GWO)优化简单循环单元(simple recurrent unit,SRU)网络超参数的预测模型。首先对二极管进行功率循环加速老化试验,对其特征参数进行分析,选取正向导通压降作为主要老化特征,其次采用改良策略后的GWO对SRU网络的学习率、隐藏层个数、迭代次数等超参数进行寻优,建立组合预测模型,最后将老化试验所得数据输入模型中进行训练以及验证,得到预测结果与其他模型对比。结果表明:本文模型具有更高的准确性,基于数据驱动的预测方法较传统分析建模方法提高了二极管寿命预测精度,进而提高了整流器工作可靠性。
