oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 23 )

2018 ( 440 )

2017 ( 428 )

2016 ( 497 )

Custom range...

Search Results: 1 - 10 of 23359 matches for " 陆海燕 "
All listed articles are free for downloading (OA Articles)
Page 1 /23359
Display every page Item
北京大兴迭隆起隐伏岩溶水化学特征及水质变化原因
陆海燕,杨帆,辛宝东,许亮
南水北调与水利科技 , 2014,
Abstract: 在2012年北京岩溶水资源勘查成果和以往资料的基础上,对北京市大兴-通州隐伏区岩溶水水化学特征、水质演化规律以及水质恶化原因进行了研究,结果表明,大兴、通州两个储水构造之间的水力联系较弱,岩溶水水化学特征不同。通州地区岩溶水为hco3#so42na#ca型,总硬度、溶解性总固体较低,整体水质良好,且与1998年相比没有发生明显变化。大兴地区岩溶水为hco32ca#mg型,总硬度、溶解性总固体均较高,其中大兴黄村-东高地一带水质较差,其它地区水质良好。与2001年相比,大兴地区岩溶水水质发生恶化,总硬度和溶解性总固体浓度明显升高,且污染范围逐渐扩大。经分析,引起大兴地区岩溶水水质恶化的原因主要有两个:(1)上游垃圾填埋渗滤液和地表污水渗入岩溶水;(2)大量开采岩溶水,改变地下水动力场和岩溶水的赋存条件,促使岩溶水水质恶化。
gd3ga5o12∶eu3+发光纳米晶的燃烧合成及性质
李艳红?,陆海燕,张永明?,刘 茜?
无机化学学报 , 2011,
Abstract: 以尿素为燃烧剂,乙二醇为分散剂采用燃烧法制备了gd3ga5o12∶eu3+纳米晶。利用x射线衍射、电镜和荧光光谱对前驱体和热处理后样品的结构、形貌和发光性能进行了表征。xrd结果表明:700℃热处理2h即可获得立方结构gd3ga5o12∶eu3+纳米晶。根据scherrer公式估算经700℃和900℃热处理2h获得的纳米晶的一次性粒径分别为28nm和42nm。发射光谱和激发光谱的结果表明:特征发射峰来自于5d0-7fj跃迁,而来自于eu3+的5d0→7f1的磁偶极跃迁发射最强;宽激发带主要来自于eu-o电荷迁移带和gd3ga5o12基质吸收。发射强度和激发强度随热处理温度的提高而增强。
图书馆读者感知服务质量的影响因素及提升策略
陆海
图书情报工作 , 2009,
Abstract: ?影响图书馆读者感知服务质量的因素主要有读者、图书馆和图书馆员等。图书馆要从研究读者需要、管理读者期望、技术/结果质量和功能/过程质量“两手抓”、提高馆员服务素质和服务接触能力、加强制度建设和公布服务质量标准等方面来提高读者对图书馆服务质量的感知。
基于arcgis的地下水浓度场绘制及质量评价
郭高轩,朱琳,沈媛媛,陆海燕,纪轶群,周俊
人民黄河 , 2014,
Abstract: ?简述了我国北方地区近年来开展的地下水环境地质调查与评价工作,阐述了进行区域地下水浓度场绘制时需要考虑的主要因素、评价方法及基于arcgis的计算机实现步骤。结果表明:考虑了水文地质单元分区、地下水流向、溶解组分分布类型的评价方法更合理,结果更符合实际。以北京平原区为例,选取总硬度、总fe含量进行了区域地下水水化学场刻画,并进行了浅层地下水的tds单因子和综合质量评价。
gdf3∶eu3+/nagdf4∶eu3+纳米晶的水热合成及发光性质
李艳红?,张永明?,马 晶?,陆海燕,马铭远?
无机化学学报 , 2011,
Abstract: 采用水热法,以聚乙二醇(400)为分散剂,以naoh和hno3溶液调节初始溶液ph值,合成gdf3∶eu3+和nagdf4∶eu3+纳米晶。xrd和sem结果表明:在酸性溶液(ph=3,5)、中性溶液(ph=7)和碱性溶液(ph=9)中,分别获得具有正交结构的gdf3∶eu3+纳米晶,gdf3∶eu3+和nagdf4∶eu3+混合晶,六方结构nagdf4∶eu3+棒状微米晶。根据scherrer公式估算ph=3和ph=5时制备纳米晶的一次性粒径分别为49和28nm。样品的发射光谱结果表明:特征发射峰来自于5d2、5d1、5d0到7fj跃迁。在主晶相为gdf3样品中,主发射峰来自于eu3+的5d0→7f1的磁偶极跃迁;晶相为nagdf4样品的主发射峰来自于eu3+的5d0→7f2电偶极跃迁。5d0→7f1和5d0→7f2跃迁发射相对强度比值显示:eu3+在nagdf4晶体中的格位对称性下降。激发光谱显示出gd3+和eu3+具有较好的能量传递。
619种高校学报定价统计分析
徐云峰?,崔金贵?,徐红星?,陆海燕,盛杰?
中国科技期刊研究 , 2014,
Abstract: 为了定量分析我国高校学报的定价情况,对《2012年全国邮发报刊目录》收录的619种高校学报进行统计,得出2012年619种高校学报单期均价为11.35元,全年均价为77.81元,与全部收录的9327种期刊43.09元的单期均价和261.57元的全年均价差距较大。所有高校主办的期刊单期定价之和还不如《分子晶体与液晶》单期定价。高校学报定价较为集中,85.78%的高校学报定价为5~15元,同质化现象非常严重。高校学报几乎没有采用尾数定价策略,市场化程度极低。
钢混框剪高层结构地震能量分布及耗散研究
Research on Seismic Energy Distribution and Dissipation of ??Reinforced Concrete Frame??wall High??rise Structure

鲍文博,付亮华,陆海燕,徐广洋
- , 2015,
Abstract: 为了研究复杂建筑结构在地震作用下地震能量的分配与耗散机制,基于能量平衡原理和Perform 3D软件对钢筋混凝土框架?布袅η礁卟憬峁鼓P徒?行了动力弹塑性能量时程分析,得到了框剪高层结构在罕遇地震作用下地震能量的输入、分布及耗散规律;考察了地震动特性对钢混框剪高层结构地震能量输入及分配的影响,确定了地震耗能占输入能的比例时程;分析了结构阻尼比和结构延性对框剪高层结构地震输入能、阻尼耗能和滞回耗能及其耗能比例的影响规律,确定了阻尼比对滞回耗能和延性比对阻尼耗能的交互影响;研究了框剪高层结构地震滞回耗能沿结构竖向分布和沿横向构件内部分配的规律,确定了竖向刚度分布对结构地震滞回耗能的影响;揭示了钢混框剪高层结构地震输入能量及其分布规律。所得结论可为基于能量平衡原理的抗震设计理论在复杂钢筋混凝土高层建筑结构实际工程中的运用提供参考。
In order to investigate the mechanism of seismic energy distribution and dissipation of complex building structure, the time history analysis of dynamic elastoplastic energy for a reinforced concrete (RC) frame??wall high??rise structure was made by using software Perform 3D based on the principle of energy balance. Mean while, the rule of earthquake input energy and its distribution were obtained for RC frame??wall structure under rare earthquake. The influences of ground motion characteristics on the earthquake input energy and its distribution in the RC frame??wall high??rise structure were examined, the time histories of the ratios of seismic energy dissipation to input energy were obtained. The influences of damping ratios and ductility ratios on the earthquake input energy, damping energy and hysteretic energy and its ratios to input energy were discussed, and the mutual influences of damping ratios on the hysteretic energy and the ductility ratios on the damping energy were determined. The distributions of the hysteretic energy along vertical direction and among RC members of the building structure were researched, and the effects of lateral stiffness on the hysteretic energy were confirmed for the frame??wall high??rise structure. The rules of earthquake input energy and its distribution among energy components were indicated for RC frame??wall high??rise structure. The obtained conclusion for seismic design theory based on the energy balance principle can provide reference for the engineering practice of complex RC high??rise building structure
北京房山地下水功能区划分
纪轶群,辛宝东,李文忠,郭高轩,许亮,陆海燕,沈媛媛
南水北调与水利科技 , 2015,
Abstract: 针对北京市房山地下水资源的分布特点,以5全国地下水功能区划分技术大纲6为基础,对地下水的资源供给功能、生态环境维持功能和地质环境稳定功能三个方面进行了深入分析,将房山地下水功能区划一级功能区分为开发利用区、地下水资源保护区、灾害防治区三种,并进一步细分为二级功能区。为满足北京房山区经济社会可持续发展的需要,合理开发利用和保护水资源提供了基础性研究。
西瓜钾素吸收特征及钾肥施用优化机制
董亚,王硕,吴萍,陆海燕,周世品,董彩霞,任丽轩
南京农业大学学报 , 2018, DOI: 10.7685/jnau.201702028
Abstract: [目的]钾肥管理是西瓜生产的关键因素,对提高经济效益和维持生态环境可持续性具有重要意义,本文旨在研究西瓜的钾素吸收特征及钾肥优化施用的机制。[方法]采用田间试验方法,研究钾肥不同施用水平下西瓜各生育期的干物质量、钾素吸收量、钾素吸收速率以及西瓜的产量与品质。[结果]西瓜对钾素的吸收量与西瓜干物质量、产量和品质存在正相关关系。西瓜在不同生育期对钾肥水平的反应不同,幼苗期对钾肥最敏感,基肥施用量为90 kg?hm-2 K2O时,西瓜根、茎、叶中的钾含量最高,施用量高于180 kg?hm-2 K2O时,西瓜叶中的钾含量低于对照;在膨果期,钾肥追肥量为180 kg?hm-2时西瓜钾素吸收速率最大,该时期的钾素吸收量占全生育期吸收量的67.9%;在成熟期,450 kg?hm-2 K2O水平下西瓜叶片中钾含量最高,600 kg?hm-2 K2O水平下果实皮和瓤中的钾含量最高。钾肥施用量为300 kg?hm-2时,西瓜干物质积累量最大,钾素总吸收量最高,此时西瓜产量最高,且可溶性糖含量最高。[结论]西瓜钾肥施用的最佳方案为基肥施用90 kg?hm-2,坐果期追肥180 kg?hm-2,基肥和追肥的比例为1∶2。
[Objectives]Potassium fertilizer management is the key factor of watermelon production. It is significant on the improvement of agricultural economic efficiency and the development of sustainable ecological environment. [Methods]Field experiment was carried out to investigate dry matter,potassium absorption and absorbing rate,as well as the yield and quality on different levels of potassium fertilizer management on watermelon. [Results]Dry matter,yield and quality of watermelon were positively relative with potassium absorption. Watermelon growth responded to potassium fertilizer on each growing period. Dry matter and potassium content was sensitive to potassium fertilization at seedling stage. Potassium content in root,stem and leaf was the highest at 90 kg?hm-2 K2O fertilization. They were lower in leaf in more than 180 kg?hm-2 K2O treatments than that in control. In fruit expanding period,the potassium absorption rate was the highest at 180 kg?hm-2 K2O level fertilization. The potassium absorption in this period was 67.9% in the plant growing period. In mature period,potassium content in leaf was the highest at 450 kg?hm-2 K2O level fertilization. The potassium content was the highest in both rind and flesh at 600 kg?hm-2 K2O level fertilization. Biomass of watermelon was the highest on 300 kg?hm-2 K2O among all levels of potassium fertilization,as well as potassium absorption,yield and soluble sugar content. [Conclusions]The character of watermelon potassium absorption was that the least absorption in seedling period and the fastest potassium absorption rate in fruit expanding period. Therefore,the optimum management of potassium fertilizer was 90 kg?hm-2 K2O basic fertilizer and 180 kg?hm-2 K2O top fertilizer in fruit forming period. The rate of basic fertilizer to top fertilizer of potassium management was 1:2
岩体各向异性与巷道围岩应力分析
陆海
岩石力学与工程学报 , 1989,
Abstract: 各向异性弹性理论主要研究材料弹性对称性质的确定及弹性问題的解法等两方面内容。本文通过建立各向异性弹性常数的不变量方程,导出一种在非弹性对称坐标系下确定正交各向异性岩体弹性对称性质(主弹性常数及主轴方向)的理论方法.应用摄动理论,本文给出求解正交各向异性体弹性平面问題的摄动解答,并计算出一般巷道孔形围岩附近的应力分布.计算结果表明,各向异性对巷道围岩应力分布状态有显著影响。
Page 1 /23359
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.