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Search Results: 1 - 10 of 142833 matches for " 周春发 "
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潜在洞巢资源差异对次级洞巢鸟及繁殖鸟类群落的影响
大庆,,邓文洪*
生物多样性 , 2009,
Abstract: ?为了解次生林中潜在洞巢资源(包括各种啄木鸟的啄洞和人工巢箱)的多寡对次级洞巢鸟集团及繁殖鸟类群落结构的影响,2007年11月至2008年7月,我们在吉林省吉林市大岗林场选择洞巢密度不同的样地,对其次级洞巢鸟及鸟类群落结构进行了比较研究。根据洞巢资源密度我们将9块样地分为3组,即巢箱区(啄洞密度最低,悬挂人工巢箱使其潜在洞巢资源总密度大幅提高)、低密度区(啄洞密度较低,无巢箱)和高密度区(啄洞密度较高,无巢箱),调查了3组样地内鸟类的组成和密度、潜在洞巢资源的利用情况等。3组样地中均调查到4种初级洞巢鸟,其种类组成略有不同;4种次级洞巢鸟在3组样地广泛分布,分别为白眉姬鹟(ficedulazanthopygia)、大山雀(parusmajor)、沼泽山雀(p.palustris)和普通鳾(sittaeuropaea)。巢箱区和高密度区的次级洞巢鸟总密度显著高于低密度区。巢箱区同高密度区一样,大山雀和白眉姬鹟的密度显著高于低密度区,这是由于大山雀和白眉姬鹟是人工巢箱的主要利用鸟种,而沼泽山雀和普通鳾的密度在三组样地间差异不显著。初级洞巢鸟总密度与啄洞密度、次级洞巢鸟总密度与潜在洞巢资源总密度都呈显著正相关关系。潜在洞巢资源丰富的样地中鸟类群落多样性指数显著高于潜在洞巢资源贫乏样地中的鸟类群落多样性指数,人为增加洞巢资源可以改变鸟类群落组成并显著提高群落的多样性指数。三组样地中鸟类群落的均匀性、丰富度指数和种间相遇率没有显著差异,群落相似性指数也相近。高密度区和低密度区鸟类群落集团结构相似。次级洞巢鸟密度的增加短时期内未对群落内其他主要鸟种的密度产生显著影响。研究结果显示,初级洞巢鸟的密度决定了啄洞的丰富程度,而洞巢资源的差异会对次级洞巢鸟集团的分布模式产生影响,进而影响整个繁殖鸟类群落的结构。
广域网的超星分形等级结构
,宗放,
重庆邮电大学学报(自然科学版) , 2000,
Abstract: 提出了广域网的超星分形等级结构模型和生长方法,从全新的角度讨论了广域网的生长、发展的过程,给出了应用本方法所构造该结构广域网的实例,表明本文提出的方法是可靠的。该结构模型将是描述互连广域的重要工具。
基于dsp的磁悬浮平台数字控制系统研究
魏莉,祖德,吴华,胡业
武汉理工大学学报 , 2009,
Abstract: ?磁悬浮平台是利用磁悬浮无机械接触、无需润滑等特点设计的加工平台,解决了传统平台易磨损、加工环境恶劣等难点。在介绍了磁悬浮平台基本组成和工作原理的基础上,设计了以数字信号处理器tms320f6713为核心器件的数字控制系统,对主要电路进行了分析,并采用智能pid控制算法,实现了磁悬浮平台样机的稳定悬浮。
磁悬浮主轴dsp控制系统的研究
吴华,胡业,祖德
武汉理工大学学报 , 2010,
Abstract: ?针对基于pc磁悬浮主轴控制系统设计复杂、价格昂贵、控制周期长等缺点,提出以tms320f6713为核心,设计了a/d、d/a转换电路;并采用模糊控制策略对磁悬浮主轴进行仿真和实验研究。结果表明在简化结构和缩短控制周期的基础上,控制精度、稳定性以及系统超调均优于传统pid的控制效果。
Influence of potential cavity resources on secondary cavity-nesters and breeding bird community composition
潜在洞巢资源差异对次级洞巢鸟及繁殖鸟类群落的影响

Daqing Zhou,Chunfa Zhou,Wenhong Deng,
大庆
,,邓文洪

生物多样性 , 2009,
Abstract: To explore how density of potential cavity resources (including cavities and artificial nest boxes) affects the composition and distribution of secondary cavity-nesting guilds, as well as the community structure of breeding birds, we studied plots with different densities of nest cavities in Dagang Forestry Farm, Jilin Province, China from November 2007 to July 2008. Based on the density of cavity resources, the nine sample sites were divided into three treatments, i.e., NBP (nest-box plots with less cavities and high-density nest boxes), LDP (low-density cavities plots without nest boxes) and HDP (high-density cavities plots without nest boxes). We then surveyed avian communities and noted the use of cavities and artificial nest boxes. All the treatments contained four primary cavity excavators, and three species were the same. Four secondary cavity nesters were widespread in the three treatments, including the great tit {Parus major), marsh tit (P. palustris), yellow-rumped flycatcher (Ficedula zanthopygia) and eurasian nuthatch (Sitta europaea). Total densities of secondary cavity nesters in NBP and HDP were higher than that of LDP. Densities of great tits and yellow-rumped flycatchers were higher in NBP and HDP than in LDP, because they were major users of nest boxes. There were no significant differences in the densities of marsh tits and eurasian nuthatches among treatments. A significant positive correlation was detected between the density of primary cavity excavators and cavity density, and also between the density of secondary cavity nesters and potential cavity resources. Bird species diversity indices were lower in LDP than in NBP and HDP. Nest-box addition could potentially regulate the composition of avian communities by increasing bird species diversity indices. We observed no differences in evenness, species richness indices or probability of interspecific encounter (PIE) among treatments, and Serensen similarity indices differed little among treatments. There were no obvious differences in structure of breeding bird guilds between HDP and LDP. Nine species were found in all the three treatments, and their densities were not affected by the temporary increase in secondary cavity nesters. We hypothesize that density of primary cavity excavators determines the density of cavities in forests, which may change distributional patterns of secondary cavity-nester guilds, and therefore affect the structure of breeding avian communities.
四种同域分布洞巢鸟的巢址特征比较
,大庆,孔祥坤,邓文洪*
生物多样性 , 2012,
Abstract: ?洞巢鸟集团是中国东北地区温带次生林内鸟类群落的重要组成部分,对于其巢址特征的比较研究有助于深入了解鸟类群落动态的内在机制。作者于2008年4–7月,对吉林大岗林场4种主要洞巢鸟的巢址特征进行了调查,并从多尺度(巢树、巢址和活动区)比较分析,进而探讨了初级洞巢鸟与次级洞巢鸟的关系。共发现160个繁殖巢,其中初级洞巢鸟58巢,包括大斑啄木鸟(dendrocoposmajor)24巢和灰头绿啄木鸟(picuscanus)21巢;次级洞巢鸟102巢,包括白眉姬鹟(ficedulazanthopygia)38巢和普通?(sittaeuropaea)45巢。初级洞巢鸟对巢树无显著选择性,而次级洞巢鸟对巢树有显著选择性,以白皮柳(salixpierrotii)为主。灰头绿啄木鸟的洞口主要朝南,而其他3种洞巢鸟对洞口朝向没有显著的选择性。初级洞巢鸟巢址特征的差异主要表现在巢树和巢址尺度上,而次级洞巢鸟在3个尺度上均有显著差异。逻辑斯蒂回归分析表明,区分大斑啄木鸟和灰头绿啄木鸟洞巢的关键因子为洞口直径和洞巢内径,即洞巢的大小;区分白眉姬鹟和普通?洞巢的关键因子为巢树树冠高度和洞口深度。也就是说,初级洞巢鸟之间以及次级洞巢鸟之间巢址特征的最主要差异均在巢树尺度上。判别分析表明,普通?倾向于选择灰头绿啄木鸟提供的洞巢,而白眉姬鹟偏好于大斑啄木鸟提供的洞巢。由于啄木鸟所凿洞巢的大小不同,导致了次级洞巢鸟对其巢址的差异性选择。因此,洞巢的大小是影响同域分布的洞巢鸟巢址利用的最重要因素。
三种不同生物饵料对曼氏无针乌贼繁殖能力的影响
The Effect of Three Different Biological Baits on Fecundity of Sepiella maindroni
 [PDF]


Open Journal of Fisheries Research (OJFR) , 2016, DOI: 10.12677/OJFR.2016.33007
Abstract:
本文采用南美白对虾、泥鳅、沙蚕三种不同的生物饵料营养强化曼氏无针乌贼亲本,以养殖水体理化因子变化、亲本成活率、卵质量为指标进行分析。结果表明:投喂三种不同生物饵料养殖水体水环境理化因子变化差异不显著(P > 0.05);采用南美白对虾营养强化的亲本成活率为85%显著高于另外两组投喂组(P < 0.05);南美白对虾组、泥鳅组、沙蚕组的个体平均产卵量分别为650 ± 33粒、530 ± 21粒、570 ± 8粒。说明,南美白对虾作为曼氏无针乌贼亲本营养强化饵料,效果更佳。
In this study, Sepiella maindroni parents were nutritively enhanced by using three kinds of live foods which are Litopenaeus vannamei, loach, and nereis. The indexes of the changes of physical and chemical elements of water, survival ratio of parents and egg quality were analyzed. The results showed that the physical and chemical factors among the three different groups feeding with different live foods were not significant differences (P > 0.05). But the survival ratio of parents in the groups feeding with L. vannamei was significantly higher than the other two groups (P < 0.05). Meanwhile, the mean spawn quantities of L. vannamei, loach and nereis were 650 ± 33, 530 ± 21, and 570 ± 8, respectively. In short, L. vannamei has a better effect as a kind of live food of nutrient enhancement of S. maindroni parents.
A method of shortest path raytracing using iterative optimization in a 3D grid model
迭代法在三维网络模型最短路径射线追踪中的应用

鲁彬,,王兴,孔省吾
地球物理学进展 , 2010,
Abstract: At present, there are many ray tracing algorithms used in 2D grid models. But in a 3D grid model few algorithms are used. The main reason is that it is difficult to implement algorithms and show pictures in 3D space. So, a new algorithm, used in a 3D grid model, is proposed. The algorithm can optimize the ray tracing from traditional 3D grid ray tracing algorithm by the iterative method. The ray tracing algorithm is applied to several 3D theoretical models and displayed in 3D space. It can improve accuracy and efficiency of ray tracing in a 3D grid model by using iterative opimiztaion.
光学运动捕捉系统中标记点自动注册与预测算法*
谭光华,美兰,,李仁
模式识别与人工智能 , 2014,
Abstract: 针对光学运动捕获系统中散乱数据注册问题,提出一种基于首帧标记点分割的标记点注册方法.该方法首先利用人体拓扑结构对首帧散乱数据进行分割,然后根据标记点局部刚性特征和时空信息完成注册,无需手工指定初始模板.对于存在缺失的数据,基于相邻帧标记点运动变化不大的假设,利用标记点的局部刚性特征对缺失数据进行预测.实验结果表明,该方法能快速且准确地标注各标记点,具有较好的鲁棒性和实时性.
鄱阳湖流域生态足迹与生态环境协调度的计算与分析
,,肖远东,宫 松,陈 静
中国生态农业学报 , 2006,
Abstract: 生态足迹是一种基于消费度量区域是否可持续发展的新参考方法,而经济与环境协调度从横向角度衡量可持续发展。本研究介绍了生态足迹的概念及生态足迹和生态环境协调度的计算评价方法,并对鄱阳湖流域2003年的生态足迹和生态环境协调度进行了计算和分析。结果表明,2003年鄱阳湖流域存在生态赤字,人均生态协调系数DS=1.3802<1.414,生态环境协调度为43,表明本地区2003年的发展模式是基本不协调和基本不可持续的。
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