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高引气型湿喷混凝土回弹控制技术研究

新型建筑材料 2024年第3期51卷 159-162页

作者：刘瑞敏中铁二十局集团第六工程有限公司陕西西安710016

为提高湿喷混凝土的可泵性,减少回弹率,掺加新型引气流变剂制备了高引气型湿喷混凝土,测试了引气流变剂与其他材料的相容性,研究了高引气型湿喷混凝土的工作性能、力学性能及回弹率等。结果表明:新型引气流变剂的发泡和稳泡能力均高于AE... 详细信息

为提高湿喷混凝土的可泵性,减少回弹率,掺加新型引气流变剂制备了高引气型湿喷混凝土,测试了引气流变剂与其他材料的相容性,研究了高引气型湿喷混凝土的工作性能、力学性能及回弹率等。结果表明:新型引气流变剂的发泡和稳泡能力均高于AES和K12,浓度为0.2%时,发泡量为1050 mL,半衰期达650 s;由于滚珠效应和溶剂化膜作用,引气流变剂能提高湿喷混凝土的流动性及保坍性,减水剂掺量为0.8%、引气流变剂掺量为0.2%时,含气量由普通混凝土的2.3%增大至10.2%;掺加引气流变剂后,湿喷混凝土的回弹率由14.56%降至8.79%,实测粉尘浓度由10.82 mg/m^(3)降至5.96 mg/m^(3),其他性能满足施工要求。

关键词：引气流变剂湿喷混凝土回弹率可泵性高含气量

采煤沉陷区模拟土壤侵蚀胁迫对灌木生理生长特性的影响

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中南林业科技大学学报 2024年第4期44卷 116-127页

作者：郑欣如张欣葛楠陈曦王博刘瑞敏王非恒内蒙古农业大学沙漠治理学院内蒙古呼和浩特010018 水利部牧区水利科学研究所内蒙古呼和浩特010020 呼和浩特职业学院巴彦镇高职园区内蒙古呼和浩特010070 内蒙古师范大学地理科学学院内蒙古呼和浩特010022 内蒙古自治区水利事业发展中心内蒙古呼和浩特010020

【目的】探究半干旱地区采煤活动造成的土壤侵蚀对北沙柳Salix cheilophila、小叶锦鸡儿Caragana microphylla生长生理特性的影响,阐明植物在逆境胁迫下的适应性及生存策略。【方法】在野外原位试验条件下,对北沙柳、小叶锦鸡儿根部进... 详细信息

【目的】探究半干旱地区采煤活动造成的土壤侵蚀对北沙柳Salix cheilophila、小叶锦鸡儿Caragana microphylla生长生理特性的影响,阐明植物在逆境胁迫下的适应性及生存策略。【方法】在野外原位试验条件下,对北沙柳、小叶锦鸡儿根部进行原位根系断裂试验来模拟土壤侵蚀胁迫,设置对照组(CK)和轻度胁迫(S1)、中度胁迫(S2)和重度胁迫(S3)四种不同程度的土壤侵蚀,测定了不同胁迫处理下两种灌木的生长指标和生理指标变化,并使用模糊数学隶属函数综合评价其抗逆性。【结果】土壤侵蚀胁迫显著抑制北沙柳和小叶锦鸡儿的株高、冠幅、枝条长度和枝条直径,且随着侵蚀胁迫程度增大,抑制程度越明显;北沙柳叶片叶绿素含量随着土壤侵蚀胁迫程度增大而降低,且随胁迫时间延长呈逐渐降低趋势,而小叶锦鸡儿的叶绿素含量在胁迫后期恢复至侵蚀胁迫前期;北沙柳的丙二醛含量随胁迫时间的延长呈先降低后升高趋势,而小叶锦鸡儿的丙二醛含量呈先升高后降低趋势;侵蚀胁迫后期北沙柳和小叶锦鸡儿叶片超氧化物歧化酶活性、过氧化物酶活性和过氧化氢酶活性升高;隶属函数分析显示,在土壤侵蚀环境中,小叶锦鸡儿抗逆性最强,北沙柳次之。【结论】小叶锦鸡儿对采煤沉陷区土壤侵蚀的破坏致损效应具有更好的抵抗力和恢复力,更适于干旱、半干旱矿区的生态修复与植被建设。

关键词：北沙柳小叶锦鸡儿采煤沉陷区土壤侵蚀胁迫生理生长特性

Temporal-spatial variation and the influence factors of precipitation in Sichuan Province,China

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生物学前沿:英文版 2008年第2期3卷 236-240页

作者： ruimin liu Zhenyao SHEN State Key Laboratory of Environment Simulation and Pollution Control School of EnvironmentBeijing Normal UniversityBeijing 100875China

Precipitation is a key factor in the water *** the same time,precipitation is the focus of study in meteorology and climatology,ecological environmental assessment,non-point source pollution and so *** the temporal-spatial variation and the corresponding factors of precipitation has become the object of hydrology and *** on the annual precipitation data,we analyzed the spatial distribution of precipitation in Sichuan Province in China as well as the temporal-spatial variation and the corresponding influence factors *** results show that the amount of precipitation was abundant,but the spatial distribution was not consistent with it and the amount of precipitation gradually declined from the south-east to the north-west in Sichuan Province,***,the spatial distribution was different throughout the *** result of correlation analysis indicated that elevation,temperature and air pressure were three key factors affecting the amount and distribution of precipitation,and the correlation coefficients were 20.56,0.38 and 0.45 ***,the relationship between the slope of topography and precipitation were significantly negative and the average correlation coefficient was 20.28.

关键词： Sichuan Province precipitation geostatistics temporal-spatial variation

Integrated assessment and changes of ecological environment in the Daning River Watershed

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Frontiers in Biology 2007年第4期2卷 474-478页

作者： liu ruimin SHEN Zhenyao State Key Laboratory of Environment Simulation and Pollution Control School of EnvironmentBeijing Normal UniversityBeijing 100875China

Based on Remote Sensing(RS),Geographical Information Systems(GIS),and the Spatial Principal Compo-nent Analysis(SPCA)method,the integrated assessment and changes in the ecological environment of Daning River Watershed are studied in this *** watershed is located in the Three Gorge Area in *** result of the integrated assessment showed that level 9 had the biggest proportion in the year 1990,which was about 40%.In the year 2000,however,there were no levels with a proportion significantly bigger than the *** comparing the assessment results in 1990 and 2000,it is discovered that the ecological environ-ment in Daning River Watershed in 1990 was better than that in 2000.

关键词： Daning River watershed remote sensing GIS spatial principal component analysis eco-environmental integrated assessment

Potential effects of automated driving on vehicle travel demand: A comparison of three case cities

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第2期11卷 348-361页

作者： Jingchen Dai ruimin Li Zhiyong liu School of Civil Engineering Tsinghua UniversityBeijing 100084China Hang Lung Center for Real Estate Tsinghua UniversityBeijing 100084China School of Traffic and Transportation Beijing Jiaotong UniversityBeijing 100044China

Automated vehicles(AVs)hold the potential to reduce road accidents,mitigate traffic congestion,and improve travel ***,the possible countervailing impacts from the changes in underserved populations’vehicle travel demand tend to be *** determine the vehicle travel demand changes that resulted from underserved populations aged between 6 and 80,this paper explores the latent effect of AVs on vehicle kilometers traveled(VKT)in a fully AV environment using person trip survey data from the cities of Sanya,Shijiazhuang,and Shenzhen in *** paper uses the natural decline hypothesis of travel demand and proposes a regression model to investigate the difference among the cities’latent vehicle travel *** show that the average VKT of the overall population in Sanya,Shijiazhuang,and Shenzhen increased by 33.4%,47.0%,and46.8%,*** analysis of the regression model confirms that the current travel behavior of individuals can affect the degree of increase in their average *** AVs into public transport,increasing the acceptance of automated shared mobility options,transforming road space use type,and prototyping AV designs with various features and needs are potential methods to cope with the countervailing *** total VKT of the overall population increased by approximately 10%-25%depending on the *** conclusions of this paper provide informative insights into the evaluation of VKT for underserved populations and contribute to the deployment of AVs to address equity and inclusion issues.

关键词： Automated vehicles Vehicle kilometers traveled Aging population Travel behavior Natural decline hypothesis

基于物种敏感度分布及相平衡理论的汾河流域磺胺类抗生素生态风险阈值研究

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生态毒理学报 2024年第1期19卷 115-126页

作者：刘瑞民赵静韩文辉王林芳马双绕夏星辉北京师范大学环境学院水环境模拟国家重点实验室北京100875 山西省环境监测与应急保障中心(山西省生态环境科学研究院) 太原030027 山西农业大学高粱研究所高粱遗传与种质创新山西省重点实验室晋中030600

磺胺素类抗生素(SAs)广泛应用于医疗、畜禽养殖等领域。但过量的SAs通过多种方式最终进入流域水体和沉积物中,对流域生态系统带来潜在的风险。预测无效应浓度(PNEC)可以作为评估污染物潜在生态风险的阈值,因此确定水体和沉积物中SAs的P... 详细信息

磺胺素类抗生素(SAs)广泛应用于医疗、畜禽养殖等领域。但过量的SAs通过多种方式最终进入流域水体和沉积物中,对流域生态系统带来潜在的风险。预测无效应浓度(PNEC)可以作为评估污染物潜在生态风险的阈值,因此确定水体和沉积物中SAs的PNEC是风险评估的关键。本研究以黄河支流——汾河流域为研究区,通过采集水体和沉积物的样品,发现水体中SAs的磺胺甲恶唑(SMX)含量最高,均值为73.6 ng·L^(-1),而磺胺醋酰(SAAM)检出率最高,高达100%。沉积物中仅检出了2种SAs类抗生素,为磺胺醋酰(SAAM)和磺胺喹恶啉(SQX),但检出频率却高达100%。基于物种敏感度分布(SSD)得到水体中SAs的生态风险阈值为3.40~440μg·L^(-1)。在此基础上,基于水-沉积物密度、体积比等参数,采用相平衡理论(EqP)进一步得到了沉积物中SAs的生态风险阈值为0.065~75.5 mg·kg^(-1)。基于确定的生态风险阈值,对汾河流域SAs现状进行风险评估,结果表明仅水体中的甲氧苄啶(TMP)的风险商(RQ)均值为0.014,存在一定的低风险,但超标概率仅为8%,而其他类别在水体和沉积物中RQ均低于0.01,均无显著风险。

关键词：磺胺类抗生素(SAs) 预测无效应浓度(PNEC) 物种敏感度分布(SSD) 相平衡理论(EqP) 生态风险阈值

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白菜型油菜IPT基因家族鉴定及表达分析

中国农业科技导报 2024年第2期26卷 56-66页

作者：刘博王旺田马骊武军艳蒲媛媛刘丽君方彦孙万仓张岩刘睿敏曾秀存甘肃农业大学生命科学技术学院兰州730070 甘肃农业大学省部共建干旱生境作物学国家重点实验室兰州730070 河西学院甘肃张掖734000

异戊烯基转移酶(isopentenyltransferase,IPT)是细胞分裂素生物合成的第一限速酶,为分析IPT基因家族在白菜型油菜生长中的功能,利用生物信息学方法从其基因组中鉴定出13个BrIPT基因,它们不均匀地分布在7条染色体上。BrIPTs可分为4个亚族... 详细信息

异戊烯基转移酶(isopentenyltransferase,IPT)是细胞分裂素生物合成的第一限速酶,为分析IPT基因家族在白菜型油菜生长中的功能,利用生物信息学方法从其基因组中鉴定出13个BrIPT基因,它们不均匀地分布在7条染色体上。BrIPTs可分为4个亚族,各家族成员均含有8~10个保守基序和1~2个UTR区。BrIPT基因的启动子区域包含众多响应元件。BrIPT基因家族成员受环境因子、生物激素及防御与应激调控。qRTPCR结果显示,tRNA-IPT基因BrIPT4、BrIPT6、BrIPT9在白菜型油菜体内各个部位均有表达。相比于苗期,成熟期白菜型油菜IPT基因的表达量更高,为后续深入研究IPT基因家族成员的生理生化功能提供了理论依据。

关键词：白菜型油菜 IPT基因家族细胞分裂素生物信息学分析

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太极拳干预老年人肌骨衰老的研究进展

武术研究 2024年第4期9卷 74-77页

作者：卞士荣徐玉明刘睿敏梁壮杭州师范大学浙江杭州311121

研究目的:探究太极拳对老年人肌肉和骨骼健康的影响。研究方法:通过查询知网、维普、万方、pubmed等网站,将“太极拳”“骨性膝关节炎”“肌肉衰减症”“跌倒”“骨质疏松”“老年人”作为关键词进行文献查阅与收集整理并分析。研究结果... 详细信息

研究目的:探究太极拳对老年人肌肉和骨骼健康的影响。研究方法:通过查询知网、维普、万方、pubmed等网站,将“太极拳”“骨性膝关节炎”“肌肉衰减症”“跌倒”“骨质疏松”“老年人”作为关键词进行文献查阅与收集整理并分析。研究结果:对骨质疏松症、肌肉衰减症、骨性膝关节炎、跌倒的类型与表现,以及太极拳预防老年人肌骨疾病最新进展进行综述性总结,得出太极拳可以延缓老年人肌肉和骨骼的衰老情况。结论:太极拳运动值得在老年群体中推广,希望能为太极拳运动延缓老年人肌骨衰老以及为未来研究提供更多理论依据。

关键词：太极拳老年人肌骨衰老干预

Effect of helmet-wearing regulation on electric-bike riders:a case study of two cities in China

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Transportation Safety and Environment 2024年第3期6卷 62-70页

作者： Wenxin Ma Zhiyong liu ruimin Li Department of Civil Engineering Tsinghua UniversityBeijing 100084China School of Traffic and Transportation Beijing Jiaotong UniversityBeijing 100044China

Objectives:Electric bikes(e-bikes)are widely used for commuting and delivery in *** the rapid increase in e-bikes on the road,related accidents have become crucial issues threatening the *** research aims to explore the protective effect of helmet-wearing regulation and to investigate some factors influencing head injury with reference to two case cities in China,obtaining information to protect e-bike ***:The traffic police-reported crash data cover the periods before and after the implementation of helmet-wearing regulations in Taizhou(with data from 2017 to 2019)and Nanning(with data in 2020)of *** statistical analysis,logistic regression and chi-square test with a Bonferroni correction were applied in the ***:A lack of helmets was common among victims in the context of a high helmet-wearing rate among general e-bike riders in Taizhou,indicating that fatality could be avoided to some extent by wearing ***,helmet wearing could reduce the probability of suffering fatal head injury by 6.4%.After the regulation implementation in Taizhou,the proportion of fatal head injuries decreased from 89%to 79%,remaining at a high level,which indicates that other measures in addition to helmet-wearing regulations should be *** to the results from Nanning,mandatory regulation worked more effectively than encouraged regulation in terms of reducing head ***:Mandatory helmet-wearing regulations are highly recommended to policymakers to reduce head injury among e-bike *** in addition to helmet-wearing regulation,*** law-abiding awareness and improving road infrastructure,should be considered to further protect e-bike riders.

关键词： e-bike safety accident analysis helmet-wearing regulation head injury