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高温、高湿环境下隧道喷射混凝土裂缝控制研究——以阿联酋铁路二期D标T1隧道为例
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作者 吕锋 王文正 +3 位作者 周志华 刘大刚 江峰清 罗佳 《隧道建设(中英文)》 CSCD 北大核心 2023年第S02期208-214,共7页
为有效控制高温、高湿环境下隧道施工过程中喷射混凝土的开裂风险,探究高温、高湿环境下隧道喷射混凝土材料力学演化规律,提出考虑热力耦合效应下隧道支护结构荷载的计算方法。为改善高温、高湿环境对混凝土材料的影响,提出纤维增强喷... 为有效控制高温、高湿环境下隧道施工过程中喷射混凝土的开裂风险,探究高温、高湿环境下隧道喷射混凝土材料力学演化规律,提出考虑热力耦合效应下隧道支护结构荷载的计算方法。为改善高温、高湿环境对混凝土材料的影响,提出纤维增强喷射混凝土设计方法,包括材料配合比设计、材料和成型环境的辅助降温措施。同时,基于理论推导建立高温、高湿隧道钢纤维喷射混凝土的裂缝评价方法,依托理论分析对钢纤维喷射混凝土进行现场裂缝检验。根据高温、高湿环境下隧道喷射混凝土力学性能变化公式,隧道喷射混凝土温度等效荷载计算方法以及钢纤维喷射混凝土裂缝评价方法计算裂缝宽度,结果表明:经过合理设计隧道喷射混凝土配合比,可使钢纤维喷射混凝土裂缝宽度w=0.14 mm,小于裂缝极限宽度w_(max)=0.2 mm,满足安全规范要求,符合现场裂缝检验结果;纤维增强喷射混凝土以及辅助降温措施可以有效控制高温、高湿环境下隧道喷射混凝土裂缝的开展。 展开更多
关键词 隧道 高温、高湿环境 喷射混凝土 裂缝控制
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高校化学实验室常见无机废液的处理方法 被引量:5
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作者 邵艳秋 姜封庆 +1 位作者 蔡雪 谭荣欣 《广东化工》 CAS 2019年第5期263-263,262,共2页
高校化学实验室每年都需要进行大量的无机实验,无机实验所产生有害无机废液对地球环境污染严重,该文主要介绍我校实验室所产生的无机废液,根据其化学性质进行了简单分类并提出环保安全的处理方法。
关键词 实验室 无机废液 处理方法
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Rise and decline of ancient salt industry revealed by Na and Ca concentrations in sediments at Zhongba site, Chongqing 被引量:4
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作者 ZHU Cheng jiang fengqing +5 位作者 MA Chunmei XU Weifeng HUANG Linyan ZHENG Chaogui LI Lan SUN Zhibin 《Journal of Geographical Sciences》 SCIE CSCD 2008年第3期328-340,共13页
Based on dynastic period division and AMS ^14 C dating performed on the sedimentary layers at Zhongba and Yuxi sites,and also the analysis of Na,Ca and Mg of 201 sedimentary samples from Zhongba site and that of Ca an... Based on dynastic period division and AMS ^14 C dating performed on the sedimentary layers at Zhongba and Yuxi sites,and also the analysis of Na,Ca and Mg of 201 sedimentary samples from Zhongba site and that of Ca and Na in 47 sedimentary samples from Yuxi by using an inductively coupled plasma-mass spectrometry(ICP),we found that there were 35 time periods when the contents of Ca and Na were reversely correlated,i.e.whenever the content of Ca was the highest,the content of Na was the lowest,and vice versa. Among them,there were 21 time periods when the content of Ca was the highest,and Na was the lowest,indicating that there were about 21 prosperous periods of ancient salt production at Zhongba site since 3000BC.Other 14 time periods with the peak values of Na while the low values of Ca indicate 14 declined periods of salt production at Zhongba site since 3000BC.The conclusion obtained from the reverse relationship between Ca and Na contents in this paper is consistent with that"the salt production at Zhongba site started in the new stone age,developed in the Xia and Shang dynasties,reached at the heyday in periods from the Western Zhou to the Han Dynasties,maintained stable to develop in the Tang and the Song dynasties,and gradually declined after the Song Dynasty because the sea salt were conveyed into Sichuan region,however,still had production in the 1970s-1980s",educed from archeological exploration.All the above mentioned results indicate that there is a reverse relationship obviously between the contents of Na and Ca in sediments at Zhongba site for ancient salt production,which can be used to reveal the process of rise and decline of ancient salt industry at Zhongba site. 展开更多
关键词 Zhongba site Zhongxian County reverse relationship between contents of Na and Ca rise and decline of early salt production
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大尺度驱动因子对新疆极端冷事件的单一与耦合影响
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作者 闫小月 姜逢清 +1 位作者 刘超 王大刚 《冰川冻土》 CSCD 北大核心 2022年第5期1539-1557,共19页
全球变暖背景下,偶发极端冷事件产生的重大灾害损失不容忽视。探究区域极端冷事件的大尺度驱动因子的耦合影响,对预估和应对气候变化产生的极端灾害具有重要意义。本文基于新疆1961—2016年53个气象站点的逐日气温资料,通过反距离加权... 全球变暖背景下,偶发极端冷事件产生的重大灾害损失不容忽视。探究区域极端冷事件的大尺度驱动因子的耦合影响,对预估和应对气候变化产生的极端灾害具有重要意义。本文基于新疆1961—2016年53个气象站点的逐日气温资料,通过反距离加权等方法对极端冷事件的时空演变特征进行分析;利用交叉小波变换对6个极端冷指数与大尺度驱动因子--北极涛动(AO)、北大西洋涛动(NAO)和厄尔尼诺-南方涛动(ENSO)进行多尺度分析;使用参数假设检验对大尺度驱动因子单一/耦合模态下的冷指数变化进行统计学显著性检验,随后对大尺度环流机制进行距平合成分析。结果表明:年均冷指数在时间尺度上均有显著性变化,新疆气温有明显的变暖趋势;空间尺度上冷指数在北疆、东疆和伊犁河谷地区的变化幅度远大于其他区域,存在空间差异性。AO、NAO与冷指数的相关性较强,ENSO与冷指数相关关系最弱但存在明显的时滞效应,大尺度驱动因子对极端冷指数的总体影响程度为AO>NAO>ENSO。单一模态下,极端冷事件在AO负位相、NAO负位相和La Niña事件期间易发生。耦合模态下,EI Niño-AO正位相和EI Niño-NAO正位相配置下冷日日数偏多;EI Niño-NAO负位相配置时极端低温值更小;La Niña-AO负位相和La Niña-NAO正位相时极端冷事件发生的可能性更大。EI Niño(La Niña)事件对AO(NAO)有一定的调制作用。新疆极端冷事件更易出现在La Niña-AO负位相、La Niña-NAO正位相时期,成因与亚欧大陆中高纬度位势异常导致冷空气路径偏西、乌拉尔阻塞加强与偏北气流影响新疆有关。 展开更多
关键词 大尺度驱动因子 极端冷事件 参数检验 单一/耦合影响 新疆
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宫缩乏力性产后出血的护理干预对促进产妇产后康复的效果分析
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作者 姜凤青 刘娜娜 赵月 《科技与健康》 2022年第4期35-37,共3页
在宫缩乏力性产后出血的护理中,探究引入护理干预对产妇产后康复的影响。抽取2020年2月—2022年4月期间在聊城市妇幼保健院展开分娩的68例产妇实施探讨,并将其进行随机分组处理,其中对照组纳入的34例产妇实施常规护理干预,观察组纳入的3... 在宫缩乏力性产后出血的护理中,探究引入护理干预对产妇产后康复的影响。抽取2020年2月—2022年4月期间在聊城市妇幼保健院展开分娩的68例产妇实施探讨,并将其进行随机分组处理,其中对照组纳入的34例产妇实施常规护理干预,观察组纳入的34例产妇展开综合护理干预,将两组产后出血量指标评定结果、新生儿Apgar评分指标、产后焦虑与抑郁指标检测值、产后康复指标评估结果、护理满意度加以对比。出现宫缩乏力性产后出血后,在干预治疗过程中,给予综合护理干预,可以减少产妇产后出血量,缓解产后不良情绪,缩短产后恢复时间,对提高护理满意度有积极作用,值得推广。 展开更多
关键词 宫缩乏力性产后出血 综合护理干预 新生儿Apgar评分指标 产后焦虑与抑郁 产后康复时间
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Research on the disappearance causes of the Tenghualuo Site in Lianyungang,Jiangsu Province, China 被引量:3
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作者 LI Lan ZHU Cheng +2 位作者 jiang fengqing ZHAO QuanHong LIN liuGeng 《Chinese Science Bulletin》 SCIE EI CAS 2008年第S1期161-176,共16页
With brilliant civilization during the transitional period from a original clan society to a state society in prehistory,the Neolithic Tenghualuo Site in Lianyungang was discovered by archaeological survey in 1989,whi... With brilliant civilization during the transitional period from a original clan society to a state society in prehistory,the Neolithic Tenghualuo Site in Lianyungang was discovered by archaeological survey in 1989,which was titled as‘one of the nation’s ten great archeological discoveries in 2000’.However,the transgression and the anthropogenic environment deterioration have ever been employed to explain the abandonment of the site.Based on a dynasty framework established by the 14 C dating,and using the experimental methods such as micro-paleontology identification in foraminifera and charophytes, the content test of Rb and Sr,susceptibility analysis as well as granularity and sedimentary facies analysis,some researches on the sediments from the two exploration layers at Tenghualuo Site were conducted,and the following new findings have been gained:Firstly,foraminifera which are relevant to the marine environment were not found in the sediment layer,however,25 charales,which usually live in the freshwater environment,in 07LTT1 exploration samples were found.Among them,3 charales were found in the samples from the forth sediment layer below the late Longshan Cultural layer and 22 charates were from the second sediment layer above the late Longshan Cultural layer.Furthermore,5 plant seeds and 41 fungal spores,together with many carbonation holes,plant seed shells,as well as their roots and stems were also found in the second sediment layer above the late Longshan Cultural layer.Secondly,the cumulative probability curves of the sediments’granularity in both the last and its overlying culture intermittent layers have characteristics of three-phase river sediment curve,and the ratios between Rb and Sr are both quite high in samples from two layers sedimented during the disappearing time of the site.All above-mentioned evidences indicate that disappearance of the Tenghualuo Site was not related to the transgression.The late Longshan Culture of the site could be completely abandoned after a relatively long-term inland water flood. 展开更多
关键词 Tenghualuo SITE FORAMINIFERA CHAROPHYTES GRANULARITY sedimentary FACIES Rb and Sr ratio disappearing reasons
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Archaeological sites distribution and its physical environmental settings between ca 260-2.2 ka BP in Guizhou, Southwest China 被引量:4
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作者 LI Kaifeng ZHU Cheng +4 位作者 jiang fengqing LI Bing WANG Xinhao CAO BO ZHAO Xiaofan 《Journal of Geographical Sciences》 SCIE CSCD 2014年第3期526-538,共13页
This study presents an analysis of the spatial-temporal distribution of 230 ar- chaeological sites in Guizhou Province, Southwest China for three selected time periods from the Paleolithic Age to the Shang-Zhou Dynast... This study presents an analysis of the spatial-temporal distribution of 230 ar- chaeological sites in Guizhou Province, Southwest China for three selected time periods from the Paleolithic Age to the Shang-Zhou Dynasties. The relationship between archaeological sites distribution and environmental changes is also discussed based on paleo-environmental proxies of 6480 and δ3C recorded in stalagmites from Southwest China. The results show that: in the Paleolithic Age (260-10 ka BP), archaeological sites were concentrated in the central, northwestern and southwestern parts of Guizhou, where the high-altitudinal karst landforms with many natural caves suitable for human habitation are developed. In the Neo- lithic Age (10-3.6 ka BP), most of human settlements were concentrated in the central, northwestern and southwestern parts, while, a fewer sites were found on river terraces in the southern and eastern parts, and the intermontane basins in the central and western Guizhou. During the Shang-Zhou Dynasties (3.6-2.2 ka BP), the sites were mainly distributed in the intermontane basins and on river terraces, which were suitable for primitive aerial farming. The analysis of paleo-environmental proxies of 6180 and δ3C since 260 ka BP suggested that climate fluctuations had little imPact on human settlements in this study area. The distinct physical environment, especially the spatial patterns of karst landforms and arable land played an important role in the archaeological sites distribution of Guizhou. 展开更多
关键词 Guizhou Province archaeological sites temporal-spatial distribution the Paleolithic Age to theShang-Zhon Dynasties physical environment
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