检索结果-南通市图书馆

Insight into the temperature sensitivity of forest litter decomposition and soil enzymes in subtropical forest in China

在线全文

学校读者我要写书评

暂无评论

Journal of Plant Ecology 2012年第3期5卷 279-286页

作者： Congyan Wang Guomin Han Yong Jia Xiaoguang Feng xingjun tian School of Life Sciences Room 1302Building MengminweiNanjing UniversityHankou Road 22Nanjing 210093China Biology Teaching and Research Section School of Life SciencesNantong UniversitySeyuan Road 9Nantong 226019China

Aims With the continuing increase in the impact of human activities on ecosystems,ecologists are increasingly interested in understanding the effects of high temperature on litter decomposition since litter decomposition and the accompanying release of nutrients and carbon dioxide are key processes in ecosystem nutrient cycling and carbon *** study was conducted to evaluate the temperature sensitivity of forest litter decomposition and soil enzymes during litter decomposition in subtropical forest in *** Two dominant litter types were chosen from Zijin Mountain in China:Quercus acutissima leaves from a broadleaf forest(BF)and Pinus massoniana needles from a coniferous forest(CF).The litter samples were incubated in soil microcosms at ambient control temperature(20C)and 10C *** a 5-month incubation,chemical composition of litter samples,litter mass losses,and related soil enzyme activities were *** Findings Three main results were found:(i)high temperature accelerated decomposition rates of both litter types,and the temperature sensitivities of litter decomposition for BF leaves and that for CF needles are equivalent basically,(ii)high temperature enhanced soil enzyme activities in the two forest types,and the temperature sensitivities of polyphenol oxidase were significantly higher than those of the other soil enzymes and(iii)the temperature sensitivities of nitrate reductase were significantly higher in the CF soil than in the BF soil,while there was no significant difference in the temperature sensitivities of the other soil enzymes between BF and *** a long-term consequence,the high-temperature-induced acceleration of litter decomposition rates in these subtropical forests may cause carbon stored belowground to be transferred in the atmosphere,which may alter the balance between carbon uptake and release,and then alter the global carbon cycle in the coming decades.

关键词： broadleaf forest coniferous forest high temperature litter decomposition soil enzyme temperature sensitivities

Adaptation of microbial communities to multiple stressors associated with litter decomposition of Pterocarya stenoptera

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2014年第5期26卷 1001-1013页

作者： Gaozhong Pu Jingjing Tong Aimeng Su Xu Ma Jingjing Du Yanna Lv xingjun tian School of Life Science Nanjing University Guangxi Institute of Botany Guangxi Zhuang Autonomous Region and Chinese Academy of Sciences

To understand the further impacts of multiple stressors in freshwater, we investigated the effects of heavy metal （HM, Cu and Zn） and nutrient enrichments （nitrogen and phosphorus, NP） on microbial decomposition of Pterocarya stenoptera litter and the associated extracellular enzyme activities and microbial biomass with microcosms. Results showed that the decomposition rates were slower in the polluted stream waters than those in the unpolluted ones, which corresponded to lower microbial biomass and integrated enzyme activities of cellulose and ^-glucosidase. The decomposition rates were accelerated at low HM level, which was associated with the stimulated enzyme activities of hydrolytic enzymes or was stimulated by both NP levels in polluted stream waters. In particular, the hydrolase enzyme activities of microbial communities in polluted stream waters were stimulated by low HM level, suggesting that low HM level-stimulated litter decomposition may be due to the increased enzymatic activities. When microbial communities were exposed to HM and NP simultaneously, the inhibitory effect （in unpolluted stream waters） or the stimulated effect （in polluted stream waters） of low HM concentration was enhanced and attenuated, respectively, which suggests that the NP antagonistic effect against HM toxicity on litter decomposition may contribute to the litter- associated extracellular enzyme activities. These results suggest that the may have antagonistic effects on stream ecosystem functioning. of HM and NP

关键词： leaf decomposition heavy metal and nutrient mixture extracellular enzyme activity community adaptation microbial community

Insights into seasonal variation of litter decomposition and related soil degradative enzyme activities in subtropical forest in China

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2013年第4期24卷 683-689页

作者： WANG Cong-yan Lü Yan-na WANG Lei LIU Xue-yan tian xingjun School of Life Sciences Nanjing University School of Environmental Sciences Jiangsu University

We used a litterbag method to investigate litter decomposition and related soil degradative enzyme activities across four seasons in a broad-leaved forest and a coniferous forest on Zijin Mountain in sub-tropical China. Across four seasons, we quantified litter mass losses, soil pH values, and related soil degradative enzyme activities. Litter decomposition rates differed significantly by season. Litter decomposi- tion rates of broadleaf forest leaves were higher than for coniferous for- ests needles across four seasons, and maximal differences in litter de- composition rates between the two litter types were found in spring.

关键词： broad-leaved forest coniferous forest litter decomposition soil degradative enzyme

在线全文

学校读者我要写书评

暂无评论

地铁直流进线振荡电流识别算法研究

机车电传动 2024年第2期 140-150页

作者：王楠清漆宇忻兰苑宋金川田行军中车株洲电力机车研究所有限公司湖南株洲412001 天津凯发电气股份有限公司天津300392 石家庄铁道大学电气与电子工程学院河北石家庄050043

针对地铁直流进线的振荡电流容易引起继电保护系统频繁误动作的问题,文章提出以变分模态分解、样本熵、TOPSIS为核心的故障诊断分析算法,并搭建实时数字仿真试验平台,以地铁继电保护装置为应用场景,通过将改进的进线保护算法与传统逆流... 详细信息

针对地铁直流进线的振荡电流容易引起继电保护系统频繁误动作的问题,文章提出以变分模态分解、样本熵、TOPSIS为核心的故障诊断分析算法,并搭建实时数字仿真试验平台,以地铁继电保护装置为应用场景,通过将改进的进线保护算法与传统逆流保护算法进行试验对比分析,验证了方法在工程实践中的可行性和有效性。结果表明,该方法可有效识别直流进线特殊振荡电流,提高继电保护的可靠性。

关键词：地铁牵引供电系统直流进线谐振电流短路电流进线保护变分模态分解

Using a behavior random permutation model to identify displacement grooming in ungulates

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Current Zoology 2023年第2期69卷 200-207页

作者： Yunchao Luo Lin Wang Le Yang Xiao-Fen Li Patrick Anselme Xinxin Wang xingjun tian Zhongqiu Li Lab of Animal Behavior and Conservation School of Life SciencesNanjing UniversityNanjing 210023China Tibet Plateau Institute of Biology Lhasa 850000China Department of Electrical Engineering Shanghai Jiao Tong University800 DongChuan RoadShanghai 200240China Department of Biopsychology Ruhr-Universitat Bochum 44801BochumGermany

Behavior affects an individual's life in all aspects,e.g.,enhancing fitness,leveraging predation risk,and reducing competition with ***,the sequential distribution of behaviors received less attention and is unclear what the function of displacement behavior *** activities can be found in vertebrate species but there is no formal method to determine whether a behavior is expressed as a displaced or normal *** the sequential distributions of behaviors in a natural setting may allow researchers to identify unexpected distributions as a possible signature of displacement *** this study,we used a behavior random permutation model to detect the presence of a displacement activity in the Tibetan antelope Pantholops hodgsonii and the Tibetan gazelle Procapra *** results showed that grooming in both ungulates tended to be accompanied with vigilance,and the frequency of grooming after vigilance was significantly higher than before vigilance.A significant positive correlation between the scan rate and grooming rate in the 2 ungulates was *** suggest that grooming could sometimes be expressed as a displacement activity in *** addition to providing a general method for further research on displacement activities in a variety of animal species,this study sheds light on the importance of a spectral analysis of sequential distribution of animal *** random permutation models can be used to explore the relevance between any 2 behaviors in a specific sequence,especially to identify a myriad of unexpected behaviors relative to their normal context of occurrence.

关键词： behavior sequence displacement activity self-grooming vigilance random distribution behavioral analysis method

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

餐厨降解菌的生物特性研究

环境科学学报 2014年第7期34卷 1781-1787页

作者：于鑫邵晨田兴军南京大学生命科学学院南京210093

为了研究餐厨降解菌的生物特性,选取耐盐性、基质迁移性及其在餐厨降解中的酶活特性展开研究,以此来揭示各菌种在降解过程中的优势特性及其各自发挥的作用.结果表明,混合菌产酶优于单菌种;菌株在2.5%NaCl浓度下可正常生长,耐盐性排序为... 详细信息

为了研究餐厨降解菌的生物特性,选取耐盐性、基质迁移性及其在餐厨降解中的酶活特性展开研究,以此来揭示各菌种在降解过程中的优势特性及其各自发挥的作用.结果表明,混合菌产酶优于单菌种;菌株在2.5%NaCl浓度下可正常生长,耐盐性排序为:博德特氏菌(Bordetella petrii)>汉氏硝化细菌(Nitrobacter hamburgensis)>螺旋巴克斯霉(Backusella circina),迁移性排序为:博德特氏菌(Bordetella petrii)>汉氏硝化细菌(Nitrobacter hamburgensis)>螺旋巴克斯霉(Backusella circina).综合来看,博德特氏菌在降解前期作用明显,蔗糖酶活后期保持稳定表明堆肥矿质化趋于稳定,脱氢酶和多酚氧化酶活在后期逐步降低并趋于稳定表明堆肥腐熟性良好且稳定.

关键词：餐厨垃圾微生物耐盐性迁移性酶活

在线全文

学校读者我要写书评

暂无评论

常见离子对漆酶降解活性艳蓝的调控作用

应用与环境生物学报 2019年第4期25卷 959-965页

作者：路文硕田兴军王强南京大学生命科学学院

漆酶具有很高的工业价值,但水体中离子的存在为其推广使用带来了巨大挑战.探讨水体中常见的7种阳离子和8种阴离子调控自由漆酶和漆酶–介体系统对水中活性艳蓝降解速率的差异.结果显示:Mn2+、Cu2+、Zn2+、HPO42-和NO2-在0-10 mmol/L范... 详细信息

漆酶具有很高的工业价值,但水体中离子的存在为其推广使用带来了巨大挑战.探讨水体中常见的7种阳离子和8种阴离子调控自由漆酶和漆酶–介体系统对水中活性艳蓝降解速率的差异.结果显示:Mn2+、Cu2+、Zn2+、HPO42-和NO2-在0-10 mmol/L范围内可促进漆酶对活性艳蓝的降解,降解速率由高到低依次为NO2-、Mn2+、Cu2+、Zn2+、HPO42-;SO32-、Cl-、Fe2+和Fe3+对活性艳蓝的降解有抑制作用,其中Fe2+和SO32-的最低抑制浓度分别为5和0.5 mmol/L;其他离子对漆酶降解活性艳蓝没有显著性影响.在5种介体的协同作用中,紫脲酸(VA)的效果最佳,导致漆酶对活性艳蓝的降解速率提升10%左右,其余介体的促进效率明显低于VA.在同等离子的调控下,漆酶–介体系统中的降解速率优于自由漆酶.本研究初步揭示了漆酶对活性艳蓝的降解机理,同时可以通过控制水体中离子的种类和数量来更好地实现漆酶对活性艳蓝的降解,结果可为漆酶在实际染料废水处理中的应用提供理论依据.

关键词：漆酶漆酶–介体系统活性艳蓝离子降解率活性位点

在线全文

学校读者我要写书评

暂无评论

不同调理剂对微生物降解餐厨垃圾的影响

环境工程学报 2014年第9期8卷 3971-3977页

作者：邵晨于鑫蒋平田兴军南京大学生命科学学院南京210093 南京恩皆优生物科技有限公司南京210046

为了探索不同调理剂对微生物降解餐厨垃圾效果的影响,本实验选取了木屑(桦木)、米糠、泥炭、花生壳、稻壳等材料分别作为主要调理剂,以餐厨垃圾的重量减量率作为评价降解效果指标,测定实验过程中的温度、含水率、pH值、微生物生物量及... 详细信息

为了探索不同调理剂对微生物降解餐厨垃圾效果的影响,本实验选取了木屑(桦木)、米糠、泥炭、花生壳、稻壳等材料分别作为主要调理剂,以餐厨垃圾的重量减量率作为评价降解效果指标,测定实验过程中的温度、含水率、pH值、微生物生物量及重量的变化。实验结果表明,影响餐厨垃圾降解效果主要因素有温度和含水率;以木屑和米糠为主要调理剂的保温性能最优,其余材料热量散失较快;以50%木屑处理的调理剂含水率适宜,能达到最适含水率要求(50%);同时,以50%木屑(桦木)为主要调理剂处理的减量率最高。

关键词：餐厨垃圾微生物降解调理剂减量率

在线全文

学校读者我要写书评

暂无评论

直流牵引网振荡电流与故障电流波形识别

电工技术学报 2013年第11期28卷 247-253页

作者：田行军李夏青李运华北京石油化工学院电气工程系北京102617 北京航空航天大学自动化科学与电气工程学院北京100191

地铁直流牵引网中经常出现的低频振荡电流导致继电保护系统误动频繁,欲提高保护系统的可靠性必须采取更为有效的特征提取方法。经验模态分解(EMD)和能量权重结合的特征提取方法可有效区分牵引网振荡电流与故障电流,实现对牵引网电流动... 详细信息

地铁直流牵引网中经常出现的低频振荡电流导致继电保护系统误动频繁,欲提高保护系统的可靠性必须采取更为有效的特征提取方法。经验模态分解(EMD)和能量权重结合的特征提取方法可有效区分牵引网振荡电流与故障电流,实现对牵引网电流动态特征信息的提取。通过对牵引网电流进行EMD分解并计算各本征模态函数(IMF)的能量权重,构建基于能量权重的多尺度特征熵,进而获得故障模式识别的特征矢量。现场实测数据证明,该方法可准确识别牵引网振荡电流与故障电流,且概念清晰、算法简单。

关键词：直流牵引网故障电流振荡电流 EMD 特征熵