基于双层深度置信网络的梁桥结构损伤识别方法研究          下载免费PDF全文

闫嵩  彭华春  杨汉青  何伟 《地震工程学报》2024,(1):66-73,104

为高效准确识别桥梁结构损伤,将深度学习与结构动力特性相结合,提出基于双层深度置信网络的桥梁结构损伤识别方法。首先取结构前3阶竖向振动频率和跨中节点前3阶竖向振动模态位移为参数,将其共同作为首层深度置信网络(DBN)的输入数据对结构的损伤位置进行识别;然后以1阶竖向振动的模态位移差作为参数,基于二层DBN对结构损伤程度进行预测;最后以郑许市域铁路桥梁为例进行验证。计算结果显示,当不考虑误差时,基于双层深度置信网络的结构损伤方法进行识别且结果精确;当噪声程度不超过10%时,定位识别结果准确率达100%;当噪声程度不超过15%时,定量识别结果最大绝对误差限不超过1.15%,识别结果准确;与传统的BP神经网络方法相比,本方法识别精度更高,抗噪性更强。  相似文献   

D—InSAR技术在西安地面沉降监测中的应用          下载免费PDF全文

何伟  周清锋  杨礼平  赵成 《江苏地质》2008,32(3):206-209

基于D—InSAR技术,对西安市因过量抽取地下水导致的地表缓慢沉降做了深入的应用研究,利用已有的西安地区SAR图像做了差分干涉测量的试验分析。结果显示,D-InSAR技术已经能够很好的应用于城市地区厘米级地面沉降的监测。  相似文献   

三轨法DInSAR观测确定区域的垂直变形     

张永志  罗凌燕  刘瑞春  何伟 《地震研究》2006,29(3):281-285

介绍了三轨法差分合成孔径雷达干涉测量计算区域垂直地壳变形的原理和方法。采用该方法，利用我国可可西里地区的3幅ERS-2卫星SLC（Single Looking Complex）图像对该地区的垂直变形进行了计算研究。结果表明，在1998～2002年期间，研究区最大垂直变形大约为6cm。  相似文献   

关于研制X射线荧光微分析标准物质的探讨   总被引：1，自引：0，他引：1  

冯松林程琳  雷勇冯向前  范东宇徐清沙因  黄宇营何伟 《岩矿测试》2004,23(3):179-182

将经过高温处理的土壤样品进行反复研磨后，用于X射线荧光微分析标准物质的研制，当99％的粉末粒径≤30μm时，用仪器中子活化和同步辐射X射线荧光进行元素分布均匀性和最少取样量分析，结果表明24个元素的最少取样量可以降到约1mg。  相似文献   

四川甘孜6.0级地震前的地电流异常     

何伟  相俊峰 《四川地震》1983,(3)

1982年6月16日在四川甘孜发生 Ms=6.0级地震。在震前3个多月,我省达日台地电流测值出现了突出的短期异常,异常持续时间95天。震后地电流测值又基本恢复到正常。对这次幅度大、形态规则的异常变化,在震前5天我们曾有过估计。我们整理了1982年1  相似文献   

Preliminary investigation of mercury in bone tissues of skua and penguin in Antarctica using AFS and Synchrotron Radiation X-ray Fluorescence(SR-XRF)          下载免费PDF全文

谢周清  程邦波  孙立广  黄宇营  何伟 《极地研究》2005,16(1):33-40

<正> Mercury(Hg)was investigated in bone tissues of skua(Catharacta mac-cormick)and penguin(Pygoscelis adeliae)collected in the maritime Antarctic usingatomic fluorescence spectrometry(AFS)and synchrotron radiation X-ray fluorescence(SR-XRF)method.The total levels of mercury in bone tissues of penguin and skuaare much lower than those in other organs(e.g.,kidney,liver).The toxic effects ofmercury in bone tissues of seabirds in polar region are not known.We have used SR-XRF method to map the distribution of trace levels of mercury in bones.The levels ofmercury are found to be enriched somewhere near the periosteal surface and/or endos-teal surface.The distribution of mercury shows strongly correlation with that of someessential elements and probably poses negative effect on the bone metabolism inferringfrom the relationship of mercury with the other elements.These studies represent afirst step toward understanding the toxic effects of mercury on bone of polar animals bysuggesting the possible microscopic investigation.  相似文献   

Sodium and potassium in the bones of penguin and skua revealed by EPR and SR-XRF technique     

谢周清  徐思琦  黄宇营  何伟  金嗣昭  孙立广 《极地研究(英文版)》2010,21(1):22-30

Penguin and skua in the maritime Antarctic have high salt loadings in the body due to almost exclusive diet consumption of marine invertebrates. However, the storage and turnover of sodium and potassium in these animals are poorly investigated. Here we determined the concentration and microscopic distribution of the two elements in the bones of penguin and skua. The average concentrations of sodium and potassium in penguin bone were comparable with that in skua bone (0.18% and 0.82% for penguin bone; 0.19% and 0.76% for skua bone in dry weight). The ratios of sodium to calcium and potassium to calcium (0.0330 and 0.0075 for penguin, 0.0335 and 0.0082 for skua in average by weight) were somewhat higher than the reported ratios for terrestrial animals, indicating these marine animals' bone enrichment of salt. The ratios of sodium to potassium in average by weight were 6.75 and 4.65 for penguin and skua, respectively. This value is much lower compared with the bulk sea water ratio of about 27.0, implying that potassium is favorable to reside in the bone rather than sodium. Both sodium and potassium were found to significant correlation with the content of organic materials in bone based upon the intensity of native signal determined by electron paramagnetic resonance (EPR). It was estimated that almost all of potassium is kept within the organic phases, while about 30% of sodium is stored in organic phases and the other 70% within mineral phase. The microscopic distributions of potassium in the cross-section and/or surface were revealed by synchrotron radiation X-ray fluorescence (SR-XRF) technique. The ratio of potassium to calcium based upon the SR-XRF intensity counter varied considerably from the surface to the interior, and on the surface the highest concentration of potassium was observed in the middle section with decreasing amounts toward the edge. This indirectly documented that exchange of potassium between fluid and bone organic phase maybe occur.  相似文献   

底泥覆盖对浅水湖泊藻源性湖泛的控制模拟   总被引：1，自引：1，他引：0  

商景阁  何伟  邵世光  范成新 《湖泊科学》2015,27(4):599-606

湖泛的发生与湖泊底部氧化还原条件和致黑致臭物充足供给直接相关.利用黄土和细沙对太湖湖泛易发区(月亮湾)底泥进行覆盖,模拟在湖泛可形成条件下,底泥-水体系及其界面主要物化性质与感官变化过程.结果表明:0.5 cm黄土和1.0 cm细沙的覆盖,从水色和嗅味半定量角度达到了对湖泛黑臭的控制,与对照组相比,覆盖组底泥间隙水中主要致黑物Fe2+浓度仅为对照组的1/3,主要致臭物甲硫醇和二甲基三硫醚等浓度则不到50%.进一步分析底部水体和底泥性质发现:经覆盖处理底部水体的溶解氧浓度提高近1倍,氧化还原电位基本处于250 m V以上水平,覆盖层1 cm左右表层氧化还原电位和p H均远高于对照底泥.以黄土为主的底泥覆盖,主要因阻隔了下层底泥中物质迁移供给和对厌氧微生物参与的控制,以及黄土本身性质对湖底物化环境的影响等,在藻体大量聚集和死亡的水柱环境中,较好地阻止了致黑致臭物的形成,从而较有效控制湖泛的发生.  相似文献   

隧道预切槽法合理支护时机及管片接头结构研究     

何伟  范培硕  葛飞  徐莉蓉  杨永香  赵阳 《岩土工程技术》2024,(1):14-21

预切槽法是隧道暗挖施工的一种超前支护工法,此工法可大幅度降低地表沉降量,对隧道围岩土体及地表建（构筑物影响较小。采用室内试验和数值模拟的方法,针对浇筑预切槽管片所用混凝土的前期强度、合理支护时机以及预切槽管片接头处合理的接茬方式进行了研究。研究结果表明,按C30配比的混凝土养护1.5～2 h时即具有6 MPa以上的抗压强度,满足拆模要求;粘接介质对管片环向位移的约束效果明显,环氧树脂可作为优良的管片粘接剂;榫槽式接头榫头角度α的理想范围为55°～70°,综合考虑预切槽工艺的可操作性,榫槽式接头深度B的理想范围为6～8 cm。  相似文献   

雪浪山横山寺西侧顺层岩质高边坡变形破坏机理与治理方案分析          下载免费PDF全文

喻永祥  何伟  李勇  李后尧  张纪星  刘德飞 《中国地质灾害与防治学报》2020,31(2):33-43

边坡的稳定性分析是地质灾害防治中的一个重要内容。以雪浪山横山寺西侧顺层岩质高边坡为研究对象,运用离散单元法计算边坡在自重、暴雨和地震工况下的安全系数,并对其薄弱部位进行监测,分析其稳定性和破坏机理。结果表明:在暴雨和地震工况下,边坡产生拉张破坏,坡体产生较大位移。通过开挖放坡、锚杆(索)联合加固、在坡顶、坡脚及各级平台布设截、排水沟等治理措施后,边坡稳定性显著提高。通过测斜仪和裂缝计对治理后的边坡进行监测得出,边坡水平位移较小,裂缝的发展得到控制,边坡稳定性得到有效提高。  相似文献