76 research outputs found
基于Web 的虚拟实验系统研究与实现
依托互联网的现代远程教育正迅猛发展, 基于Web 的虚拟实验系统是现代远程教育的重要
组成部分。给出了网上虚拟实验系统的体系结构, 讨论了网上虚拟实验系统的一些主要特点, 总
结了实现网上虚拟实验系统的一些基本技术。最后介绍了一个部分实现的网上虚拟实验系统—— TDN- CM+《计算机组成原理》虚拟实验系统
碳酸盐岩油藏缝洞单元离散数值模型及压力响应曲线特征
缝洞型碳酸盐岩油藏储集体类型多样,如何充分利用试井测试资料认识钻遇储层特征是后期挖潜增产的关键,并且常规解析试井模型中无法考虑井与缝洞的位置关系导致解释结果误差较大。为此,根据缝洞单元内缝洞与井的分布特征,分别建立了井钻遇和未钻遇缝洞2种离散数值试井模型,并进行有限元求解,分析了缝洞体大小以及缝洞体与井之间距离对井底压力响应曲线的影响。采用该方法对塔里木哈拉哈塘油田14口井测试资料进行试井分析,结果表明,受缝洞体的影响,井底压力响应曲线特征可分为:缝洞发育-未钻遇缝洞-井在缝洞附近、缝洞发育-钻遇缝洞、钻遇多个连通的缝洞、基质为主-缝洞不发育以及缝洞不发育-钻遇个别缝洞5种类型
Testing AGNPS for water quality modeling in agricultural catchment in southeast of China
利用地理信息系统 (GIS) ,基于数字高程模型 (DEM) ,提取AGNPS(AAgriculturalNon PointSourceModel)模型所需的水文和地形参数 ,并通过实地调查及专题制图等手段获取AGNPS模型所需的土地利用、土壤质地及施肥水平等其它参数 ,最后利用监测降水 ,实测水文参数、营养盐及沉积物负荷等验证AGNPS模型在我国东南亚热带地区的应用 .It is feasible to evaluate the Non-point Source pollution such as sediments, agricultural chemicals using water quality model in the basin scale. AGNPS (Agricultural Non Point Source), an event driven, distributed parameter model, which is developed and validated primarily in the United States, was employed in the landscape of Jiulong River watershed. The hydrologic and topographic parameters of AGNPS model were extracted based on DEM (Digital Elevation Model) built in GIS (Geographic Information System). The erosion and nutrients transport modules of AGNPS were tested and validated in Jiulong River watershed based on measurements and other data during the main crop growing season.教育部博士点基金 (19990 38411) ;; 福建省自然科学基金 (D0 110 0 0 3
化学模拟生物固氮——Ⅸ 铁钼辅基模型化合物的合成和性能表征
本文曾在全国化学摸拟生物固氮协作组领导小组扩大会议(昆明,1980,8)上宣读。[中文文摘]采用乙二醇基阴离子作为活插头(可通过水解除去的双配位螯形配位体),对前文提出的合成方法作了重要改进,以期所合成的铁钼辅基模型化合物中Mo~(Ⅳ(Ⅲ))第一配位界内两个不稳定的配位体处于相邻的位置,如厦门模型Ⅲ(或厦门模型Ⅱ)所要求。合成和重组活性评价结果,重组活性比使用乙腈等为活插头的提高2个数量级,化学催化活性和选择性接近于天然FeMo-co水平。[英文文摘]A significant improvement has been made to the method previously proposed[3] for synthesizing FeMo-co modeling compounds. With the use of ethylene glycolate anion as labilizable blocking agent (hydrolyzable bidentatc chelating ligand)to protect two neighboring coordination sites in the first coordination sphere of MoIV(III) of the synthesized FeMo-co modeling compound, an increase in reconstituted-nitrogenase activity of 2 orders of magnitude of the sample synthesized (as compared with the use of acetoni-trile or other monodentare ligands as bloeking agents)has been obtained.Catalytic activity and selectivity assays as well as preliminary characterization by EPR method have also been made
Honeycomb-Patterned Hybrid Films and Their Template Applications via A Tunable Amphiphilic Block Polymer/Inorganic Precursor System
通讯作者地址: Li,L(通讯作者),Xiamen Univ,Coll Mat, Xiamen 361005, Peoples R China
地址:
1. Xiamen Univ, Coll Mat, Xiamen 361005, Peoples R China
2. Xiamen Univ, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China
3. Chinese Acad Sci, Shanghai Inst Organ Chem, Shanghai 200032, Peoples R China
电子邮件地址: [email protected], we show a facile and versatile method-prepare highly ordered inorganic patterns on solid substrates by pyrolyzing UV cross-linked polymr/functional. precursor hybrid films. The crosslinked polymer matrix acted as structure-directing agent in a pyrolyzing process, whereas the functional precursor was converted into the skeleton of the micropatterns. The inorganic micropatterns could be further catalytically functionalized to grow CNT and ZnO nanorod arrays by simply changing different functional precursors. This simple technique offers new prospects in the field of micropatterns, nanolithography, and template.National Natural Science Foundation of China,50703032,20974089;Natural Science Foundation of Fujian Province,2009J06029;
Ministry of Education of Chin
混播下柳枝稷叶绿素荧光参数及 对水氮条件的响应特征
采用盆栽试验,按照白羊草(Bothriochloa ischaemum)与柳枝稷(Panicum virgatum)株数比设置5个混
播比例(0∶8、2∶6、4∶4、6∶2、8∶0),在两种氮肥处理(不施氮和0.1g N·kg-1)下,测定分析柳枝稷叶绿素荧光
参数对土壤水分短期自然干旱并复水[土壤含水量从80% FC(田间持水量为20%)逐渐降至20% FC后再复水
至80% FC]的响应,以期揭示不同水氮及混播比例下柳枝稷与白羊草竞争关系的生理生态机制。结果显示:(1)
随干旱胁迫加剧,柳枝稷最大光化学效率(Fv/Fm)、光化学猝灭(qP)、实际光化学效率(ΦPSⅡ)和表观光合量子传
递速率(ETR)逐渐下降,复水后第2天各指标均可恢复到对照水平;(2)两氮肥处理下,单播柳枝稷的ETR 显著
高于混播,施氮处理下单播的qP 显著高于混播,但非光化学猝灭系数(NPQ)相反(P<0.05),且柳枝稷比例越小
各指标降幅越大,表明混播后柳枝稷PSⅡ反应中心活性下降,显示出其对混播竞争的适应;(3)施氮显著提高了柳
枝稷的ΦPSⅡ(13.64%~23.53%)和qP (6.12%~11.11%),降低了NPQ 值(9.76%~12.82%)(P<0.05),表明
施氮可提高其光能利用能力,增强其与白羊草的竞争力。研究认为,不同水氮条件下,柳枝稷表现出较强的混播竞
争适应性,施氮会提高其对白羊草的生态竞争能力。</p
双摇杆假肢膝关节的运动学与动力学分析
膝关节是人体正常运动的重要部位。为了满足下肢截肢患者恢复正常运动功能的需求,设计了一款双摇杆机构的假肢膝关节。首先,建立了下假肢的简化模型,通过对模型的运动学分析,获得了相关关节角度、角速度、角加速度等参数。通过动态静力分析法对双摇杆的各个杆件进行动力学分析,最终得到输出阻尼力与驱动力矩之间的平衡方程。通过Adams仿真分析,得到了高度相似的膝关节瞬心轨迹和踝关节轨迹运动曲线对比图。结果表明,设计的双摇杆假肢膝关节具有良好的稳定性与仿生性,能够满足截肢患者的运动需求。研究为双摇杆假肢膝关节整体的结构设计、加工和实时控制提供了理论依据
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