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Search Results: 1 - 10 of 32810 matches for " 丁婷 "
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论检索实践课课件中的关键技术及实现
,菊芳
图书情报工作 , 2002,
Abstract: ?就“医学信息检索模拟实习”课件制作过程中涉及的关键技术与实现方法,包括课件的系统结构、课件页面的组织和人机交互界面的构建等问题进行探讨。
鲢鱼放养密度对水体中浮游藻类的影响
Influence of Breeding Density of Hypophthalmichthys molitrix on Phytoplankton in Ponds
 [PDF]

, 建华, 冯佳, 谢树莲
Open Journal of Fisheries Research (OJFR) , 2014, DOI: 10.12677/ojfr.2014.11004
Abstract:
2013年4~9月调查了山西省永济市温流水良种繁育场鲢鱼放养密度对水体浮游藻类,特别是蓝藻细胞丰度以及溶氧量的影响。两组鱼塘,一组为低密度鲢鱼养殖(21.2 g/m3),一组为高密度鲢鱼养殖(42.4 g/m3)。调查结果显示:1) 高密度鲢鱼放养鱼塘溶氧高于低密度鲢鱼放养鱼塘;2) 初期水体的浮游藻类总细胞丰度差异不大,但后期鲢鱼高密度放养鱼塘浮游藻类总细胞丰度低于低密度放养鱼塘;3) 初期两种密度鲢鱼养殖池塘中的蓝藻细胞丰度差异不大,后期高密度鲢鱼养殖池塘比低密度鲢鱼养殖池塘中的蓝藻细胞丰度明显降低,在浮游藻类总细胞丰度中所占比例也有同样的变化趋势;4) 两种养殖密度下,后期高密度养殖池塘中优势种有由蓝藻门向其他门类变化的趋势。总体结论,高密度鲢鱼养殖较低密度鲢鱼养殖可以更有效地控制和减少水体中的浮游藻类细胞丰度,特别是蓝藻的细胞丰度,更有利于水质净化,同时也提高了渔产潜力。
An investigation was carried out that the breeding density of Hypophthalmichthys molitrix influenced the cell abundance of phytoplankton, especially Cyanobacteria in Wenliushui Excellent Fish Breeding Grounds, Yongji, Shanxi Province, North China, from April to September of 2013. Two experimental groups were set, which represented low and high breeding density of H. molitrix, and were 21.2 g/m3 and 42.4 g/m3 respectively. The results showed that: 1) the dissolved oxygen of high density breeding ponds was higher than that of low breeding density ponds; 2) the cell abundance of phytoplankton had little difference at first but distinct difference later, and it was obvious lower in high breeding density ponds of H. molitrix than that in low breeding density ponds; 3) the same trend was reflected in Cyanobacteria; 4) compared with the low breeding density ponds, the dominant species had the trend from Cyanobacteria to the other divisions in high density breeding ponds of H. molitrix. In conclusion, the high density breeding of H. molitrix can control the cell abundance of phytoplankton especially Cyanobacteria, and purify water body, and meanwhile, the aquatic productivities are increased.
放养密度对鲢鱼淀粉酶和脂肪酶活性的影响
Influence of Breeding Density on Amylase Activity and Lipase Activity of Hypophthalmichthys molitrix
 [PDF]

, 建华, 冯佳, 谢树莲
Open Journal of Fisheries Research (OJFR) , 2014, DOI: 10.12677/OJFR.2014.12006
Abstract:
本实验就高密度养殖与低密度养殖下对鱼体内淀粉酶和脂肪酶活性的影响进行了探究。2013年4月~10月,在山西省永济市温流水良种繁育场设置了两组池塘,每组三个,一组为低密度鲢鱼养殖(21.2 g?m?3),一组为高密度鲢鱼养殖(42.4 g?m?3)。对此两种密度养殖下鲢鱼肠道淀粉酶和脂肪酶活性进行了测定,结果表明:高密度养殖池塘中鲢鱼肠道的淀粉酶活力和脂肪酶活力均高于低密度养殖池塘,且鲢鱼前肠此两种消化酶活性高于后肠;高密度鲢鱼养殖池塘与低密度相比,蓝藻门的细胞丰度明显下降,绿藻门细胞丰度所占百分比明显增加;淀粉酶活力与蓝藻的细胞丰度呈负相关,与其余门类浮游植物细胞丰度呈正相关,脂肪酶活力与蓝藻和裸藻的细胞丰度呈负相关,与其余门类浮游植物细胞丰度呈正相关。
This experiment has carried on exploration including the influence on amylase and lipase activities in fish body under high and low breeding density. From April to October in 2013, the influence of different breeding densities on amylase activity and lipase activity in H. molitrix intestinal tract was investigated in Wenliushui excellent fish breeding grounds in Yongji, Shanxi province, North China. Two experimental groups (each including three ponds) were set, which represent low and high breeding of H. molitrix density of 21.2 g?m?3 and 42.4 g?m?3 respectively. The results showed that amylase activity of high density breeding ponds was higher than that of low density breeding ponds, and amylase activity in foregut is higher than that in hindgut, as is the same with the lipase activity. The cell abundance of Cyanophyta in high breeding density ponds was obviously lower, while the proportion of the cell abundance of Chlorophyta was higher than that in low breeding density ponds. The amylase activity had a negative correlation with the cell abundance of Cyanophyta but a positive correlation with the cell abundance of the other divisions. The lipase activity had a negative correlation with the cell abundance of Cyanophyta and Euglenophyta, but a positive correlation with the cell abundance of the other divisions.
基于层次分析法的浅层地温能适宜性评价分析—以兰州市中心城区为例
Suitability Evaluation of Shallow Geothermal Energy on Analytic Hierarchy Process—As an Example in the Central Urban Area of Lanzhou City
 [PDF]

魏林森, 宏伟,, 范斌, 康亮
Advances in Geosciences (AG) , 2016, DOI: 10.12677/AG.2016.65043
Abstract: 依据实际勘查资料和测试数据,采用层次分析法所建立的数学评价模型,对兰州市中心城区面积384.7km2的区域进行了浅层地温能适宜性评价分析。浅层地温能适宜性评价体系地下水源热泵共建立了3个属性准则和10个要素指标,土源热泵共建立了3个属性准则和8个要素指标,分别构建了各层次的判断矩阵,并全部高精度通过一致性验证。评价结果,地下水源热泵适宜、较适宜区占调查区总面积的38.99%,主要分布于断陷盆地及黄河黄河I~III级阶地区及和平、定远盆地大部等含水层富水性较好、单井涌水量1000~5000 m3/d、矿化度小于1.0 g/L的地带;土源热泵适宜、较适宜区占调查区总面积的68.57%,主要分布于黄河两岸III~IV级高阶地区与黄土丘陵过度地带及和平、定远盆地等包气带细颗粒地层厚度大于20~40 m、地下水位埋深大于25 m的地带;调查区其余地带不适宜浅层地温能的建设。评价结果对兰州市中心城区浅层地温能的开发利用具有重要的指导作用。
Based on the actual survey data and the test data, the shallow geothermal energy of Lanzhou city center (the area of 384.7 km2) is evaluated and classified by the way of analytic hierarchy pro- cess (AHP). In the evaluation system, 3 criteria and 10 indicators are established for underground water source heat pump, 3 criteria and 8 factors for soil source heat pump, all levels of judgment matrix are constructed and precision through consistency checking. The results show that the area of underground water source heat pump suitable and suitable for the survey area with a total area of 38.99%, which mainly distributed in the fault basin, Yellow River level I - III and the large parts basin of Heping and Dingyuan that the water rich water content is better, the single well water inflow 1000 - 5000 m3/d, the mineralization degree is less than 1.0 g/L. The soil source heat pump suitable and suitable areas for 68.57% of the total area of the survey area, which mainly distributed on both sides of the Yellow River level III - IV higher-order region and the Loess Hilly transition zone, Heping and Dingyuan basin, which aeration with fine grain layer thickness is greater than 20 - 40 m, groundwater depth more than 25 m. The rest of the survey area is not suitable for the construction of shallow geothermal energy. The research results have an important guiding role for the development and utilization of shallow geothermal energy in the central urban area of Lanzhou city.
东北地区夏季旱涝的环流型及动力气候模式解释应用
,陈丽娟
高原气象 , 2015, DOI: 10.7522/j.issn.1000-0534.2014.00101
Abstract: 基于1991-2010年东北地区91站逐月降水资料、NCEP/NCAR再分析资料以及国家气候中心第二代月动力延伸预报模式(BCC_DERF2.0)共20年回报资料,分析了夏季各月影响东北降水的环流型,检验了BCC_DERF2.0对东北各月降水和主要环流系统的预测能力,并建立了东北地区降水的解释应用预测模型。诊断分析显示,东北地区6月降水异常主要受东北冷涡和鄂霍茨克海阻塞高压的影响,7月主要受西太平洋副热带高压(下称西太副高)的影响,而8月主要受西太副高和东北冷涡的影响;模式性能分析显示,BCC_DERF2.0模式对东北南部的个别站点降水趋势有一定的预测能力,对6月偏南风、7月西太副高、8月西太副高和东北冷涡的预测效果较好。在此基础上,提取影响我国东北夏季降水异常的关键环流区的高技巧预测信息,建立线性回归模型,交叉检验显示提高了对8月的降水预测技巧,通过了显著性检验。进一步对比分析发现,BCC_DERF2.0直接输出的20年回报夏季各月东北降水效果好于同期国家气候中心业务发布预报,而利用模式输出的高技巧环流信息建立的东北降水回归预测模型交叉检验效果高于模式直接输出降水预报。因此,基于诊断分析和BCC_DERF2.0模式超前预报时间为10天的高技巧环流信息解释降水,可以明显提高东北夏季月尺度降水的预测能力。
非致命性捕食风险对鸟类的影响
蒋一,长青
动物学杂志 , 2014, DOI: 10.13859/j.cjz.201404020
Abstract: 非致命性捕食风险是捕食者对猎物产生的间接的、非致命性的捕食压力,对维持捕食者-猎物种群数量的相对稳定具有重要意义。鸟类拥有较复杂的反捕食对策,是研究非致命性捕食风险的理想对象。本文综述了非致命性捕食风险对鸟类影响的研究进展。研究者通过多种方法模拟非致命性捕食风险,发现不同鸟类的耐受性不仅会影响个体适合度,也会影响其种群数量动态。鸟类对非致命性捕食压力的行为响应受诸多因素影响,包括鸟类自身状态,栖树高度,集群大小等。研究鸟类对非致命性捕食风险的响应,对完善捕食风险权衡理论,建立种群数量预测模型,以及探讨人类与鸟类共存机制具有重要意义,同时可为生态旅游中提出合理的接近距离、制定有效的保护管理措施提供科学指导。
保险代位权的非定义解读:内涵、区分及构成——基于《保险法》第59、60、61条
,武亦文
华东政法大学学报 , 2013,
Abstract:
中国热浪前期信号及其模式预报
,钱维宏
地球物理学报 , 2012, DOI: 10.6038/j.issn.0001-5733.2012.05.005
Abstract: 在中国1979—2008年发生的87场区域干热浪事件中有83场区域干热浪事件可以在250hPa层高度扰动场上追踪到前期信号.高度扰动信号的移动方向可分为低纬向西和中纬向东传播的两类,前期信号平均出现的时间为7天.中国南方热浪的前期信号,一部分(19%)来自低纬西北太平洋,平均提前4.6天,而大部分(81%)的前期信号来自欧洲和中国西北地区,可提前2—15天,这些信号沿中纬度自西向东移动到达100°E—110°E和40°N附近地区.中心位置发生在北方的区域干热浪事件,前期扰动信号都来自欧亚中高纬度.统计得到,250hPa层的高度扰动达到120gpm与地面出现区域干热浪相对应的次数占41%.降低区域干热浪的定义标准,高度扰动作为前期信号的正确率会得到提高.在分析2003年中国夏季江南—华南大范围持续热浪事件的基础上,用欧洲中期天气预报中心的模式产品,对这次热浪500hPa高度场做物理分解,结果发现模式对高度扰动的预报具有提前1—7天的预示能力.
中国热浪事件的大气扰动结构及其稳定性分析
钱维宏,
地球物理学报 , 2012, DOI: 10.6038/j.issn.0001-5733.2012.05.006
Abstract: 利用对流层至平流层大气变量的物理分解,本文发现400hPa上的天气尺度温度扰动正值和250hPa上的天气尺度高度扰动正值能够指示地面上的高温和热浪事件.理论和观测分析发现,当扰动静止波中心出现在40°N—45°N时,准静止波波长较长,影响范围大,持续时间久,容易在中国形成区域持续性热浪事件.在江南—华南、长江沿江及河套—华北的区域,干热浪事件静止波的稳定时间在6.5天以上.对流层大气天气尺度扰动波动在垂直方向具有倾斜特征,250hPa高度上,静止波稳定位置比地面热浪区域中心普遍偏北6~12个纬距.在低纬度(副热带高压带南侧),大气中向西北方向移动的天气尺度扰动,只有到达副高脊线以北的西风带后,才能形成静止波.
东北夏季降水的年代际特征及环流变化
,陈丽娟,崔大海
高原气象 , 2015, DOI: 10.7522/j.issn.1000-0534.2013.00155
Abstract: 利用1961—2012年中国东北地区91个气象站逐月降水资料、NCEP/NCAR再分析资料和海温资料,以及经验正交函数分解EOF、显著性检验等方法,分析了东北地区夏季降水的时空分布特征、年代际变化特征及相应的环流分布型变化,探讨了不同年代际背景下东北夏季降水年际变化的环流差异.结果表明,东北夏季降水存在明显的年代际变化特征,在19611983年(P1)期间降水偏少,19841998年(P2)期间降水偏多,1999年之后(P3)又进入偏少时段.P2与P1时段相比,东北气旋式环流和蒙古反气旋式环流异常增强,而西北太平洋副热带地区为气旋式环流异常,来自西北太平洋偏东水汽输送贡献明显.P3与P2时段相比,东北冷涡活动偏弱,东北地区东部在850hPa为偏北风异常,偏南水汽输送有所减弱.进一步分析证实,北太平洋年代际振荡(PDO)对于东北地区夏季降水及相关环流型的年代际变化有重要的调制作用.P1与P3同为降水偏少时段,PDO都处于负位相,东北地区反气旋式环流都偏强;然而P1时段的多雨年,水汽输送主要来自较强的夏季风偏南气流;P3时段的多雨年,水汽输送可能主要来自西北太平洋地区.
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