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Search Results: 1 - 10 of 282667 matches for " 李启鹏 "
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确定大巴山隧道地下水年龄的逆统计模型
刘丹,,
铁道工程学报 , 2003,
Abstract: ?本文论述了地下水年龄计算的逆统计模型(ism)的原理与方法,并将该模型用于大巴山隧道地下水年龄估算。计算显示隧址区地下水平均年龄介于45~75年之间,南坡(55~75年)高于北坡((45~60年)说明后者的水力传导性优于前者。该模型既考虑了基岩裂隙介质中地下水流普遍存在的水动力弥散作用的影响,又能使地下水年龄计算较之传统的同位素数学物理模型更为简便,具有实用价值。
基于异常感知的动态维修服务管理
,,刘文煌,
计算机集成制造系统 , 2006,
Abstract: 加强维修服务过程中管理和控制的主动性,持续改进服务过程,是提高维修服务管理水平的重要环节。解决这一问题的关键是提高服务过程中异常事件的预测和分析能力。据此,提出了一种基于数据挖掘技术的服务过程异常事件分析和预测方法,并利用某柴油机厂的维修服务记录进行了方法验证,取得了较好的效果。这种方法为加强服务过程中管理和控制的主动性提供了一个新的思路。
Prediction of protein homo-oligomer types with a novel approach of glide zoom window feature extraction
基于多策略滑动伸缩窗特征提取方法预测蛋白质同源寡聚体

,张绍武,潘泉,陈伟
生物物理学报 , 2009,
Abstract: Protein homo-oligomers play an important role in varous life processes .The concept of multi-strategy glide zoom window was proposed and a novel approach of multi-strategy glide zoom window feature extraction was used for predicting protein homo-oligomers. Based on the concept of multi-strategy glide zoom window, the authors chose two strategy glide zoom windows: whole protein sequence glide zoom window and kin amino acid glide zoom window, and for each strategy glide zoom window, three feature vectors of amino acids distance sum, amino acids mean distance and amino acids distribution, were extracted. A series of feature sets were constructed by combining these feature vectors with amino acids composition to form pseudo amino acid compositions (PseAAC). The support vector machine (SVM) was used as base classifier. The 75.37% total accuracy is arrived in jackknife test in the weighted factor conditions, which is 10.05% and 3.82% higher than that of conventional amino acid composition method and that of BG_Zhang in the same condition. The results show that multi-strategy glide zoom window method of extracting feature vectors from protein sequence is effective and feasible, and the feature vectors of multi-strategy glide zoom window may contain more protein structure information.
氨基功能化介孔氧化硅纳米中空球负载乙酰丙酮氧钒催化苯甲硫醚选择性氧化反应
,白诗扬,,
催化学报 , 2012, DOI: 10.3724/SP.J.1088.2012.20520
Abstract: ?首次将乙酰丙酮氧钒固载在氨基功能化的介孔氧化硅纳米中空球以及SBA-15(直型孔道结构)和SBA-16(笼型孔道结构)上,并应用于苯甲硫醚选择氧化反应.结果表明,在温和的反应条件下,上述催化剂均可催化苯甲硫醚高选择性地转化为亚砜产物(选择性最高大于99.0%).动力学对比实验表明,相比于直型和笼型介孔氧化硅,纳米中空球负载的催化剂具有更高的转化频率.这是因为纳米空心球尺寸小,更有利于催化活性中心的暴露以及反应物和产物在催化过程中的扩散.催化剂可循环使用多次,其活性和选择性基本保持不变.
阻隔材料的气体渗透率
王静,军建,
强激光与粒子束 , 2012,
Abstract: ?对气体渗透阻隔材料的渗透率与气体温度、气体压强的关系进行了理论分析,得到了在不同温度和气体压强条件下渗透率的加速因子的计算式,理论计算结果与相关文献中实验测量结果比较一致。根据加速条件下进行的水蒸气、氧气和二氧化碳对聚对苯二甲酸(pet)和环氧树脂渗透率测量的结果,计算得到在常温常压条件下这些气体对0.155mm厚pet塑料的渗透率和对0.065mm厚环氧树脂的渗透率。
弯曲性河道断面布设对断面法冲淤成果的影响
苏运,,尚红霞,汪大
人民黄河 , 2004,
Abstract: ?河道冲淤量的计算通常有"断面比较法"(简称断面法)和"输沙平衡法"(简称沙量法)等.黄河下游艾山-利津河段为弯曲性河道,弯道段和浅滩段存在不同的冲淤特性,一般情况下,弯道段涨冲落淤,浅滩段涨淤落冲.由于测验断面布设于弯道河段的多于浅滩河段,因此在汛期一定的水沙条件下,造成计算冲淤量汛期和非汛期出现较大偏差.通过弯道段和浅滩段不同冲淤特性的分析,提出了在弯道段及过渡段布设数量相同的实测大断面、尽可能避开局部冲刷坑的影响、尽可能加密测验断面等断面布设原则.
跨声速多级轴流压气机特性预估及分析*
,高丽敏?,瑞宇?,刘 波?
推进技术 , 2014,
Abstract: 为了研究跨声速轴流压气机的性能分析问题,采用流线曲率法结合损失落后角模型,发展了一种利用反问题方程求解正问题的数值方法。在nasa低速平面叶栅试验数据的基础上考虑三维效应的修正,根据激波结构随工况的变化发展了一种新的激波损失计算方法,整理了一套适合跨声速轴流压气机的损失落后角模型。对两级跨声速轴流风扇进行了数值模拟研究,进行了设计工况的校核计算和全工况特性预测,并将计算结果与nasa试验值进行了比较分析。结果显示,设计点计算误差在1.1%以下,非设计点也能得到与试验值吻合的趋势,表明所建立的方法和模型可以有效地对跨声速多级轴流压气机进行全工况特性预测。
配合物[Cu(IDB)_2]Cl_2·2CH_3CH_2OH·2H_2O的合成、晶体结构及其与常见金属离子的反应 Synthesis and Crystal Structure of Complex[Cu(IDB)_2]Cl_2·2CH_3CH_2OH·2H_2O and Its Reaction with Metal Ions
,陈彦国,,
- , 2016,
Abstract: 报道了含三齿配体N,N-二(2-苯并咪唑甲基)亚胺(IDB)的单核铜(Ⅱ)配合物[Cu(IDB)_2]Cl_2·2CH_3CH_2OH·2H_2O的合成、晶体结构及与常见金属离子的反应.该配合物为三斜晶系,P1空间群,a=0.956 5(2)nm,b=0.986 3(2)nm,c=1.025 2(3)nm,α=81.915°,β=88.330°,γ=87.347°,V=0.956 28(40)nm~3,Z=1,F(000)=427,D_c=1.419g.cm~(-3),M_r=817.27,μ=0.764mm~(-1),最终因子R[I>2σ(I)]:R_1=0.050 5,ωR_2=0.141 7;R(全部数据):R_1=0.059 1,ωR_2=0.152 5.结构分析表明,铜(Ⅱ)分别与配体中的4个苯并咪唑N原子和2个胺基N原子配位,形成一个六配位的畸变八面体.荧光光谱分析表明:在不同浓度、不同金属离子中,标题配合物的荧光强度发生变化;过渡金属、碱金属和碱土金属离子对标题配合物的荧光有猝灭作用;过渡金属离子影响作用较碱金属、碱土金属的影响作用更为明显;但铝离子对标题配合物的荧光却有增强作用
“可控涡”方法在离心叶轮设计中的应用研究
Applying Circulation Control Method to Designing Centrifugal Impeller

,高丽敏,瑞宇,刘波
- , 2015,
Abstract: 采用流线曲率法求解S2流面反问题,为了考虑由于流体粘性损失造成的熵增,将Galvas的一维管流损失模型修改后应用于二维通流计算中并与主方程耦合求解,并编制了一套离心叶轮“可控涡”通流设计程序。为了探讨加入同等的欧拉功条件下不同环量分布方式对叶轮流场及性能的影响,以某给定设计目标的离心叶轮为研究对象,在满足后加载的前提下针对叶片尾缘附近环量的导数采取两种不同的分布方式进行通流设计,并进行了全三维粘性流动分析比较。结果表明:气流环量及环量沿流向的导数分别对叶片通道内的速度分布和叶片表面的载荷分布有着显著地影响。
The streamline curvature method is assessed to solve the inverse problem for the S2 stream surface. In order to consider the entropy rise caused by fluid viscosity, the duct-flow loss model by Galvas is modified and coupled with the solving of a control equation in the through-flow calculation. Finally, the through-flow design program of a centrifugal impeller based on the circulation control method is established. Furthermore, to investigate the influence of circulation distribution on the flow field of the centrifugal impeller and its performance, an impeller is designed by using two kinds of circulation distribution with a slight difference at the trailing edge. Then, 3-dimensional numerical analysis is made, and the analysis results show that the circulation distribution has a significant effect on the velocity and blade load distribution of the centrifugal impeller
海底管道受坠物锚击损伤模型试验研究
Model experimental study on damage of submarine pipeline subjected to falling anchor strike

,郭海燕,,晓秋,晶石,福恒
- , 2018, DOI: 10.7520/1001-4888-17-094
Abstract: 为探索不同影响因素对锚击作用下海底管道的损伤规律,本文通过海底管道受坠物锚击作用损伤试验,研究了坠物质量、坠落高度、管道铺设条件、水深和坠物形状对海底管道机械损伤的影响。试验结果表明,管道的凹陷损伤与应变随坠物质量和坠落高度的增加而增加;在相同质量的立方体、球体和模型锚三种形状坠物作用下,球体坠物对管道的损伤最严重;管道的损伤程度随铺设的沙土厚度和水深的增加而降低;沙土层比硬土层可以更好地降低管道的损伤程度;在距撞击点50cm范围内,管道发生塑性形变。
In order to explore damage pattern of submarine pipeline subjected to different influencing factors, through damage experiment of submarine pipeline subjected to falling anchor strike, the influence of different factors, such as the mass of falling object, the height of fall, the pipeline laying condition, the depth of water and the shape of falling object on the mechanical damage of submarine pipeline are studied in this paper. Experimental results show that the depression damage and strain increase with the increase of falling mass and height of fall. Under the same mass condition, submarine pipeline subjected to action of cubic object, sphere object and model anchor respectively, the most serious damage is caused by sphere object. The damage degree of pipeline decreases with the increase of sand thickness and water depth. Sand layer can reduce the damage degree of pipeline better than that of hard soil layer. Within 50cm of impact point, plastic deformation occurs in pipeline
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