Androecium of Archaefructus,the Late Jurassic Angioperms from Western Liaoning,China     

SUN Ge  ZHENG Shaolin  SUN Chuntin  SUN Yuewu 《东北亚地学研究》2002,(1)

Androecium of the earliest known flowering plant Archaefructus liaoningensis was found from the Upper Jurassic Jianshangou Formation of western Liaoning, China. The androecium consists of numerous stamens bearing in pair on the re-productive axes below conduplicate carpels. The stamens are composed of a short filament and basifixed anther for each. Mo-nosulcate pollen in situ are found from the anthers. The characters of the androecium reveals that Archaefructus are probably protandrous, and the paired stamens and monosulcate pollen appear to indicate that Archaefructus, as primitive angiosperms, might be derived from extinct seed-ferns during the Older Mesozoic. Archaefructus is considered Late Jurassic in age.  相似文献   

Distinct effects of temperature change on discharge and non-point pollution in subtropical southern China by SWAT simulation     

Heng Xu  Shaolin Peng 《水文科学杂志》2013,58(5):1032-1046

Abstract

Climate change impacts on the availability of water resources. Projection of hydrological response to temperature change is valuable for water management. Such response may be complex and uncertain at the watershed scale and differences may exist between low and high latitudes. A simulation experiment was achieved by using SWAT modelling in the upstream watershed of Dongjiang River, South China. After calibration, the model was found appropriate for hydrological simulation in the study area and was run from 1995 to 2004 under a series of temperature change scenarios to reveal the response of streamflow and loads of sediment and nutrients. For a temperature increase of 3°C, streamflow, sediment and total phosphorus decreased by 5.2, 7.7 and 2.2%, respectively. Linear temperature change seemed to have a linear hydrological response. Nutrient deficiency was still the primary vegetation stress compared with water availability and temperature stress under rising temperatures. Comparison with previous research showed that two southern subtropical watersheds (one upstream and one downstream) gave different hydrological responses. Sediment and inorganic nitrogen loads decreased in the upstream watershed, but increased in the downstream one, when temperature increased. Under the warming scenarios, streamflow and sediment loads decreased throughout the year, especially during the wet season, which is different from results at high latitudes. Nutrient export decreased in April–June, but increased in the remaining months. Simulation results should be applied with caution in water resources management, as simulated climate change had variable hydrological influence in different regions and seasons.

Citation Xu, H. and Peng, S.L., 2013. Distinct effects of temperature change on discharge and non-point pollution in subtropical southern China by SWAT simulation. Hydrological Sciences Journal, 58 (5), 1032–1046.

Editor Z.W. Kundzewicz; Associate editor C.-Y. Xu  相似文献   

CPF变化对Landsat TM/ETM+辐射校正结果的影响     

黄绍霖  徐涵秋  王琳 《吉林大学学报(地球科学版)》2014,44(4):1382

随着时间的推移,卫星传感器的老化会使得原有的辐射定标参数文件(CPF)失效。最典型的当属Landsat-5卫星,该卫星自1984年发射以来,已经进行了多次CPF修正;而Landsat-7卫星的CPF也经过了数次修改,以保证辐射校正结果的准确性。以Landsat TM/ETM+遥感影像为例,分别以2003、2009年的CPF对它们进行辐射校正,并对结果进行对比。结果表明,除ETM+的绿光波段外,TM、ETM+影像基于2009年CPF计算的各波段均值都要小于2003年。而这一变化也使得由此计算的指数产生差异：归一化植被指数(NDVI)间的差异可达0.48%,建筑用地指数(IBI)间的差异可达5.94%。  相似文献   

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陈文凯  何少林  周中红  张苏平 《大地测量与地球动力学》2010,30(6):24-30

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地震标准化的现状和发展探讨     

何少林  周克昌 《华北地震科学》2020,38(3):1-5

总结了地震标准化工作管理、地震标准的发布和复审现状,归纳了地震标准化在发展进程、标准数量、标准制定和构成等4个方面的特点,并针对促进未来地震标准化工作提出了8个方面的具体建议以供讨论。  相似文献   

广东流溪河水库盔型溞(Daphnia galeata)休眠种群与现生种群的单倍型多样性和遗传分化     

黄琦  徐少林  徐磊  韩博平 《湖泊科学》2017,29(5):1209-1216

休眠卵库作为淡水枝角类生物与遗传信息的储藏库,从沉积物休眠卵库中萌发的枝角类对现生种群的数量与种群遗传结构有着直接的影响.分别采集流溪河水库盔型溞的现生种群和沉积物表层(0~10 cm)的休眠卵,扩增现生种群与休眠卵的线粒体细胞色素C氧化酶亚基I基因,构建了单倍型网络.休眠种群相比现生种群有着较高的单倍型多样性和核酸多样性,初期现生种群分别为0.562、0.00104,末期现生种群分别为0.726、0.00331,休眠种群分别为0.815、0.00761.流溪河盔型溞现生种群与休眠种群存在双向基因流,现生种群到休眠种群的有效迁移率为490.9,休眠种群到现生种群的有效迁移率为527.5.通过构建贝叶斯系统树验证了休眠种群和现有种群中并不存在隐种或者亚种的分化,休眠种群与现生种群之间没有出现较大的遗传分化,现生种群遗传多样性来自于休眠种群,水库的休眠种群更能反映种群真实的遗传多样性.休眠种群与现生种群之间的基因流与休眠卵库大小无关,与休眠卵的萌发有关.  相似文献   

2017年9月23日朝鲜振动事件记录特征分析     

赵永  杜广宝  孙丽  何少林  刘杰 《震灾防御技术》2017,12(4):751-757

2017年9月23日16时29分在朝鲜丰溪里核试验场发生3.4级地震。本文基于中国地震台网对该地震事件的波形记录,分析认为:该事件不是一次简单的单独过程,虽然事件开始时发生爆破,但事件主体是由断层错动产生的天然地震。这次事件是爆破和天然地震相继发生的复合型事件。  相似文献   

调整触发检测参数的图形界面工具     

何少林  李海亮 《地震地磁观测与研究》1998,19(6):55-62

介绍一个图形化的调整触发检测算法参数的实用工具软件。其操作简单,检测结果直观,并用该工具软件得到了一些初步结果,他是提高检测效果有效的辅助软件工具。  相似文献   

地震速报软件测试探讨 ——以自动地震速报软件为例     

张成  何少林 《地震地磁观测与研究》2021,42(3):298-305

通过分析地震速报软件测试现状,讨论测震业务软件进一步细分类的参考依据,提出地震速报软件供方、业务管理方和用户方的职责建议,给出地震速报软件的内容信息表。进一步以自动地震速报软件测试为例,从文档检查、功能测试、性能测试、易用性测试等方面探讨测试内容以及自动地震速报结果评分表。文中提出的建议和内容具有一定可操作性,可在实际工作中参考使用。  相似文献   

甘肃地区地震烈度影响场计算模型参数的改进研究与应用     

周中红  何少林  陈文凯  高安泰 《震灾防御技术》2011,6(2):180-189

针对目前甘肃地震应急指挥技术系统中使用的地震影响场模型参数存在的不足,本文结合甘肃地区活动构造特点,建立了适用于本地区的分区地震烈度影响场模型参数.并通过实例检验证明,使用新参数得到的不同烈度区的烈度分布与实际烈度分布的接近程度有明显提高,可为震后合理判断烈度分布、提高震害快速评估结果的合理性与准确性提供有益的帮助.此外,本文基于ArcGIS Engine、采用VB6.0实现了地震影响场矢量文件的自动生成,可为今后发生破坏性地震时,通过与省地震应急基础数据库中其他空间数据的叠加分析,在应急救援初期制作各类灾区专题图件及辅助决策提供服务.  相似文献