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Search Results: 1 - 10 of 365800 matches for " 王立海 "
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小兴安岭带岭林区红松阔叶林景观多样性与稳定性研究
,孟春
应用生态学报 , 2005,
Abstract: 选取具有典型代表性的黑龙江省小兴安岭带岭林业局东方红林场为研究对象,在应用地理信息系统软件对现行森林经营措施进行分析的基础上,探讨了该林场景观分类、景观变化动态分析的结果和成因,并应用马尔可夫转移模型进行景观模拟预测.结果表明,研究期间东方红林场一级分类和二级分类的景观多样性指数较低,有林地面积占整个研究区域的91%以上,构成了景观的基质;1985~1993年间,有林地优势地位加强,优势度从0.611增加到0.692,顶极群落优势度增加70%;在以择伐为主伐更新措施条件下,红松阔叶林在201~209年间将达到稳定状态,面积为13120~1322hm2,成为当地稳定的顶极植被群落.
近断层地震动模拟现状
,谢礼
地球科学进展 , 2008, DOI: 10.11867/j.issn.1001-8166.2008.10.1043
Abstract: 地震动是由3个物理过程(震源破裂过程、波传播过程、场地反应)组成的一种复杂系统的产物,地震动模拟均是围绕这3个物理过程的建模开展的。地震动模拟目前仍然是一门相对较新的科学,强震观测中不断发现的新情况、新问题及其深入研究进一步推动近断层地震学理论和实践的发展。减少建模中的不确定性,用基于观测物理学的统计特征逐渐取代基于现象的假设描述,以改善地震动模拟的精度。基于大量地震动模拟的研究文献和资料,归纳、评述了近断层地震动模拟方法的现状、3个物理过程的建模方法及其发展趋势。
近场地震学中3个术语译名的商榷
谢礼,
地震工程与工程振动 , 2005,
Abstract: asperity,barrier和flingstep是近场地震学中3个重要的术语。但到目前为止,这3个术语还没有贴切、统一的中文译名。为了便于学术交流和读者对近场地震学的学习和理解,有必要规范统一它们的中文译名。本文基于3个术语产生的物理背景及其意义,建议这3个术语的中文译名分别为asperity――高强体,barrier――止裂体,flingstep――滑冲。
近断层强地震动场预测
,谢礼
地球物理学报 , 2009,
Abstract: 以1997年4月11日新疆伽师地震(Mw6.1)为例,详细介绍了近断层强地震动场的预测方法.首先,用有限断层震源建模方法建立了该次地震的震源模型;然后,基于动力学拐角频率的地震动随机模拟方法,模拟了该次地震仅有主震加速度记录、且位于巨厚土层上的三个台站的加速度时程,并用实际地震记录进行了验证.在此基础上,基于预测的近断层77个节点的加速度时程的峰值绘制了该次地震的加速度场.结果表明,上述方法模拟的加速度时程在0.5Hz以上的高频段是可行的、实用的;预测的近断层加速度场具有非常明显的上盘效应.地表最大加速度的范围与断层面上最大凹凸体位置相对应,说明与断层面上凹凸体相对应的地面上的建(构)筑物将会遭受到较为严重的震害.
自贡市西山公园地形对地震动的影响
,谢礼
地球物理学报 , 2010, DOI: 10.3969/j.issn.0001-5733.2010.07.014
Abstract: 不规则地形和土层对地震动的影响较大,建(构)筑物选址及其抗震设防必须考虑地形和土层场地的放大效应,以避免或减轻其震害.利用自贡地形台阵记录的汶川地震(Ms8.0)的主震加速度时程,基于传统谱比法分别研究了地形和土层场地对地震动的放大效应.结果表明:(1)地形场地在低频的放大效应不明显,最大仅为1.24;在高频的放大效应较显著,在1~10Hz频带,山顶的放大效应最大,EW、NS和UD地震动的最大放大效应分别为4.15、3.61和2.41,对应频率分别为5.72Hz、6.46Hz和7.44Hz;在10~20Hz频带,靠近山顶的山脊上某个地震动分量的放大效应最大,7#台站EW、5#台站NS和7#台站UD地震动的最大放大效应分别为9.10、5.56和2.52,对应频率分别为16.97Hz、16.91Hz和17.91Hz.(2)地形场地的最大放大效应随高度有增加的趋势,且在0.1~10Hz频带随高度增加的趋势更加明显.(3)土层场地水平向地震动在2Hz以上开始明显放大,竖向地震动在4Hz以上开始明显放大;EW、NS和UD地震动的最大放大效应分别为13.4、12.168和6.0,对应频率分别为6.94Hz、7.55Hz和10.8Hz.(4)土层场地与地形场地的最大放大效应相比较,前者显著大于后者,对于水平向地震动,前者至少是后者的3倍以上;对于竖向地震动,前者至少是后者的2.5倍以上.(5)无论是地形场地还是土层场地,地震动的最大放大效应均有水平向大于竖向的特征.
基于渐进式变结构遗传算法的肢体机器人运动规划
刘莉,
哈尔滨工程大学学报 , 2010, DOI: doi:10.3969/j.issn.1006-7043.2010.12.017
Abstract: 为使机器人的末端同时具备行走和操作能力,提出一种新颖的三肢体冗余度机器人,并介绍了该机器人的机构以及人机接口的设计.针对该机器人的运动规划提出渐进式遗传规划策略,该策略能够将笛卡尔空间坐标位姿自动、有效地映射到关节空间.在渐进式遗传规划方法的基础上提出一种变结构遗传算法,该算法可用以解决动态环境下渐进式遗传运动规划易陷入局部极小点的问题.实验结果表明渐进式遗传规划方法在静态环境中的有效性,同时也证实了变结构遗传算法对动态环境下进行运动规划的有效性.
一种基于混合方法的彩色图像分割算法*----结合分水岭算法、种子区域生长和区域合并的混合方法
A Color Image Segmentation Algorithm Based on Hybrid Method*—By Integrating Watershed with Automatic Seeded Region Growing and Merging
 [PDF]

徐国雄, , 胡进贤, , 卜应敏
Computer Science and Application (CSA) , 2013, DOI: 10.12677/CSA.2013.32023
Abstract:
本文提出一种新的结合分水岭与种子区域生成、区域合并的彩色图像分割算法。首先将RGB颜色空间转换成HSI间,应用分水岭算法对图像进行初始化分割,形成过分割效果。接着基于分水岭算法得到的分割结果,利用颜色空间的像素与其领域的颜色差异及相对欧式距离自动选出一些区域作为种子区域进行自动种子生长算法。为了克服过分割的不良效果,该方法充分利用了分水岭算法和区域合并算法的各自优势。利用提出的算法对多幅图像进行实验,结果证明此算法有较好的分割效果。
A color image segmentation algorithm which integrates watershed with automatic seeded region growing and merging is proposed in the paper. Firstly, the image was transformed from RGB color space to HSV space. Next, watershed algorithm was applied to the image to obtain initial segmentation effect. And then, based on the results of watershed segmentation, some regions in the image were selected as seeded regions automatically for seeds growth algorithm by making use of color differences and relative Euclidean distance. Finally, a region combining algorithm was executed to avoid excessive segmentation. The proposed method combines the advantages of watershed and region growing approach, and it is in accord with the human vision segmentation strategy. This algorithm was applied to segment some endoscopic images, the experimental results confirm its effectiveness and efficiency.
白桦模拟缺陷材的电阻层析成像规律探究
兴龙,
- , 2016, DOI: 10.13360/j.issn.2096-1359.2016.02.019
Abstract: 以白桦圆盘为对象,人工设计各种空洞缺陷,研究电极传感器数量、内部缺陷面积、轮廓形状以及位置等因素在利用电阻层析成像检测缺陷准确性方面的影响。结果表明:电阻层析成像技术可以通过电阻率的分布直观地显示木材内部缺陷,但是其图像显示的缺陷面积和缺陷轮廓受诸多因素影响; 圆形缺陷面积从5.69%上升到40.48%时,电阻层析成像系统显示的缺陷面积与实际缺陷面积的相对误差率从4.14下降到0.02; 增加电极传感器的数量可以提高检测准确率; 缺陷轮廓形状对电阻层析成像有一定的影响,狭长形缺陷容易被检测出来,但近圆形缺陷的面积准确率高; 缺陷位置对电阻层析成像有一定的影响,缺陷面积一定时,边材处的空洞比心材处的空洞更容易被检测出来,而且缺陷面积的准确率也高。
In order to improve the feasibility of wood nondestructive testing methods, electrical resistance tomography as a new and developing technology was chosen for the detection of wood internal defects. Fifteen pieces of artificial discs of Betula platyphylla Sukaczev in total with average diameter of 15 cm and thickness of 5 cm respectively were selected as the experimental samples. With designed varieties of artificial simulating cavity defects, the discs were tested by means of electrical resistance tomography. The different detecting images were acquired from the different detecting conditions. For the investigating and analyzing requirements, different number of sensors, different defect area, defect position, and outlook of simulated cavity defects were used as the detection of defects accuracy for electrical resistance tomography. The results showed that the relative error of graph defect area and real defect area drop from 4.14 to 0.02 with the rate rose from 5.69% to 40.48%. In the case of adjacent sensors without mutual interfered, the increasing numbers of sensors could improve the detection accuracy. Outline shapes of defects have certain effect on detection of defects. Compared with other cavity defect shapes, long and narrow shape defect could be easily detected. On the contrary, the area and outlook of accuracy of circular defect detection accuracy is highest. The defect position also has certain effect on the detection of defects. Within the same defect area, the center of cavity defects located at sapwood could be easier detected with higher detection accuracy than those located at heartwood. Electrical resistance tomography could visually display the internal defects of wood by resistivity distribution, but the precision and outlook of tomographic image are closely related to a wide range of factors, including the number of sensors, defect area, defect position and outlook of simulated cavity defects, all of which would have an effect on accuracy of test results. It is necessary to modify the test results when judge the actual defect with electrical resistance tomography
腐朽对山杨木材吸水性和电阻的影响
The Effects of Decay on Electrical Resistance and Moisture Content of Populus davidiana Wood

兴龙,
- , 2016, DOI: 10.3969/j.issn.1001-7461.2016.03.45
Abstract: 以山杨木材试件为研究对象,研究在健康状态和腐朽状态下木材电阻和含水率的关系、木材腐朽前后绝干质量、含水率、电阻的变化及关系。结果表明,腐朽木材电阻受含水率的影响规律与健康木材相似,即随着含水率升高木材电阻下降;纤维饱和点以上相同含水率下,健康木材的电阻远远高于腐朽木材电阻,而木材腐朽后吸水性增强含水率升高使得电阻进一步降低,木材腐朽之后电阻明显减小;腐朽后木材电阻与健康木材电阻和增水率整体显著相关,木材减阻率与其失重率和增水率间具较强的二元线性关系。
In order to research the relationships between the wood electrical resistance and moisture contents for sound and decayed wood samples,respectively,the changes and relationships among resistance,moisture content and absolutely dry mass,Populus davidiana wood was selected as objective.The results showed that the relationship between decayed wood electrical resistance and moisture contents was similar to that for the sound wood samples that the wood electrical resistance decreased with the increase of wood moisture content.Decayed wood electrical resistance was lower several times than that of the sound wood below the fiber saturation point at the same moisture content.Moreover,the increasing moisture contents in decayed wood samples lowered the wood electrical resistance more,so the electrical resistance of decayed wood decreased significantly.Through regression analysis,decayed wood resistance was significantly correlated with the sound wood electrical resistance and moisture contents.The correlation between the ratio of the decrement of decayed wood electrical resistance to normal wood electrical resistance and the ratio of increment of decayed wood moisture contents to the normal wood moisture contents and the weight loss ratio were significant as well
技术成熟度及其识别方法研究*
,冷伏,
现代图书情报技术 , 2010,
Abstract: ?对技术成熟度的概念和起源进行简介,区分其与技术生命周期等相近的概念;重点研究美国国家航空航天局制定的技术成熟度体系,介绍其特征描述、研究框架并讨论应用价值、评估工具和应用局限性;最后简要探讨浅语义分析和共词分析两种方法在识别技术成熟度方面的可能性。
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