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Search Results: 1 - 10 of 89354 matches for " 何爱斌 "
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农业干旱风险研究进展
,武建军,
地理科学进展 , 2010, DOI: 10.11820/dlkxjz.2010.05.007
Abstract: 农业干旱风险分析是近年来兴起的一个新的研究领域,这一研究不仅是农业旱灾风险管理的基础和前提,也是农业干旱风险区划和灾前损失预评估的理论基础.本文系统阐述了农业旱灾风险的内涵及构成要素、风险分析体系及研究现状,在此基础上指出,依据自然灾害风险分析基本原理,从农业旱灾危害性以及承灾体脆弱性角度系统地建立农业旱灾综合风险分析程序框架和指标体系,尤其是开发针对每一风险要素的、动态的数学模型和指标体系是当前干旱灾害风险时空格局研究的当务之急.
SW型脱硫剂脱硫性能的研究
,,杨景亮,
环境科学 , 1994,
Abstract: 以硫酸烧渣为主要原料制备SW型脱硫剂,并对其脱硫性能进行了研究。对半水煤气、葡萄酒厂污水处理产生的沼气和焦沪煤气、水煤气中的H2S进行了工业脱硫试验。经半年以上运行证明:可使其H2S含量从3000-5000mg/m3降为20mg/m3以下(符合国家标准),当脱硫剂工作硫容达30%时可返回硫酸生产中,再生周期一般为3个月,其主要性能达到国内外同类产品水平。
采用频域融合方法的砂轮刀具磨损三维重构技术
Three??Dimensional Reconstruction of Tool Wear Area for Grinding Wheel Using Frequency??Domain Fusion Method

,胡浩强,大勇,陈渭
- , 2015, DOI: 10.7652/xjtuxb201505013
Abstract: 针对聚焦合成方法在砂轮刀具磨损区域三维重构过程中高度值离散的问题,运用傅里叶变换将聚焦合成方法与明暗形状恢复方法相结合,提出了聚焦合成方法的高度值连续化新方法。运用傅里叶变换,在频域中对聚焦合成方法形成的三维重构图像进行高通滤波,对明暗形状恢复方法形成的三维重构图像进行低通滤波,并将滤波后的图像在频域叠加,经过傅里叶反变换,得到空间域融合后的刀具磨损区域三维重构图像。分析和实验表明,融合后的三维重构图像同时保留了聚焦合成方法中蕴含的离散几何高度信息和明暗形状恢复方法中蕴含的表面细节特征信息,能有效避免由于聚焦合成方法中高度值离散带来的误差。
Aiming at the problem of the discontinuous height values in the three??dimensional reconstruction of tool wear area for grinding wheel using the method of depth from focus (DFF), a new method for continuing the height values with DFF is proposed by using Fourier transform to combine the methods of DFF and shape from shading (SFS). Using Fourier transform in the frequency domain, performing highpass filtering for the 3D reconstruction image of DFF and lowpass filtering for the 3D reconstruction image of SFS, and superimposing the filtered image in the frequency domain, the 3D reconstruction image of the tool wear area of grinding wheel can be obtained by inverse Fourier transform to fuse in the spatial domain. Analysis and experimental results show that the fused 3D reconstruction image not only retains the discrete geometric height information contained in DFF and the detailed surface information contained in SFS, but also effectively avoids the errors caused by the discontinuous height values in the DFF
考虑接触刚度的含间隙铰接副动态磨损分析
Dynamic Wear Analysis of Clearance Joint Considering Contact Stiffness

,胜利,邹超,陈渭
- , 2016, DOI: 10.7652/xjtuxb201605002
Abstract: 针对大多数含间隙铰接副的磨损计算都非常复杂,精度和效率不能兼得,且很少能够与含间隙铰接副系统的动力学分析动态结合起来考虑表面接触刚度对磨损影响的问题,提出了一种新的含间隙铰接副磨损分析方法。基于无质量杆?驳?簧阻尼模型建立考虑接触刚度影响的含间隙铰接副系统动力学分析模型,利用非对称Winkler弹性基础模型计算接触压力分布,?用Archard磨损理论计算接触表面磨损量,对接触表面轮廓实时更新得出含间隙铰接副的动态磨损量。分析结果表明,在表面接触刚度较小时含间隙铰接副的动态磨损严重,且随系统转速的变化呈现出不同的变化趋势,反映了不同接触刚度下含间隙铰接副的动态磨损趋势。该方法计算精度和计算效率较高且充分考虑了表面接触刚度对含间隙铰接副动态磨损的影响,对含间隙铰接副系统的设计和动力学分析及磨损预测具有一定的指导意义。
Most of wear calculations for clearance joint are very complicated and the accuracy and efficiency can not be satisfied simultaneously, and the dynamic wear analysis rarely combines with the dynamics analysis of clearance joint system considering the effect of different surface contact stiffness. A dynamic wear analysis for joint clearance considering different contact stiffness is proposed. The mass??less??link and spring??damping model is adopted to conduct dynamics analysis of clearance joint system considering different contact stiffness. The nonsymmetric Winkler surface model is taken to evaluate the contact pressure distribution, and the Archard wear theory is employed to calculate the worn mass of contact surface. The surface profile renews at real time with the wear calculation result, then the dynamic wear prediction of clearance joint is acquired. The dynamic wear trend for different contact stiffness is discussed. The proposed strategy fully considers the effects of contact stiffness on the dynamic wear of clearance joint, and reflects the dynamic wear trend of clearance joint surface for different contact stiffness with higher accuracy and efficiency
刀具磨损图像视差图的非标定方法
Uncalibrated Method for Disparity Map of Tool Wear Images

,大勇,邹超,陈渭
- , 2016, DOI: 10.7652/xjtuxb201603002
Abstract: 刀具磨损检测的视场范围很小、现场工况复杂(存在机床护罩和刀具保持架的遮挡),而以往对摄像机进行标定的方法多用于大视场环境,并不适合于加工现场的刀具磨损检测。为此,文中提出一种采用非标定双目视觉方法获取刀具磨损图像视差图的方法,无需标定参考物和人工干预。首先,利用SURF(speeded-up robust features)算法检测图像对中的特征点;其次,利用8点算法计算基本矩阵,再利用极点无穷远变换完成图像对的校正;最后,利用基本区域匹配方法完成图像对视差的计算。进行了加工现场的磨损刀具图像获取实验,先对比了重构出的刀具视差图轮廓与实际轮廓,接着分析了刀具视差图的精度。结果显示,重构轮廓与实际轮廓基本相符,重构出的视差图的绝对误差在5个像素点以下,相对误差在10%至30%之间,说明在小视场和复杂工况下,用非标定方法获取的刀具视差图能够满足现场检测的精度要求,并且该方法具有灵活和高效的特点。
The field of view of tool wear detection is small, and the site condition is complex (e.g., the blocking of machine cover and tool holder exists). Whereas the traditional method that needs camera calibration is mostly used in large field of view, which is not suitable for on??site tool wear detection. An uncalibrated method based on binocular vision is proposed in this paper for obtaining the disparity map of tool wear images without calibration reference or man??induced intervention. Firstly, SURF (speeded??up robust features) algorithm is used to detect the images’ feature points. Then, the 8??point algorithm is adopted to estimate the fundamental matrix; next, image correction is completed by pole infinity transform. Finally, the disparity map is obtained by basic block matching algorithm. On??site experiments were conducted to obtain the tool wear images, and the analysis on profile and accuracy of the reconstructed disparity map was performed. The results show that the reconstructed profile is basically consistent with the actual profile; the absolute error of the reconstructed disparity map is less than 5 pixels and the relative error is between 10% and 30%, meaning that the disparity map obtained by the uncalibrated method in small field of view and complex site condition can meet the accuracy requirement for on??site detection, and this method is also flexible and effective
小果油茶上油茶象的产卵策略
李志文,立红,杨柳君,,
昆虫学报 , 2015,
Abstract: 【目的】油茶象CurculiochinensisChevrolat是我国特有木本油料树种——油茶Camelliaspp.的专性蛀果害虫,常导致其大量落果。本文旨在揭示该虫发生危害与寄主果实大小的关系,并探讨其产卵行为策略。【方法】于油茶象产卵高峰期在小果油茶Camelliameiocarpa林随机采摘960个果实,清查油茶象刺孔数和窝卵数,并对果重、果长和果径进行了测量,用单因素方差分析比较产卵果、取食果和非受害果大小差异性,用线性回归分析果实特征对油茶象取食及产卵活动的影响。同时对油茶象雌虫进行了果实大小选择性试验,用配对样本t检验分析选择果与非选择果的大小差异性。【结果】在果重、果长、果径和果实体积方面,产卵果>取食果>非受害果(P<0.01),刺孔数、窝卵数和寄生率与果实大小呈极显著线性正相关(P<0.01),说明油茶象雌虫优先选择大果实取食和产卵。当两供试果实差异显著时,油茶象雌虫对大果实表现出明显的偏好选择性,危害12h后,重受害果长度和直径都显著大于轻受害果(P<0.01)。油茶象雌虫每次只产1粒卵,卵单产是油茶象本身的属性,与果实特征无关。【结论】油茶象优先选择大果实取食,支持最优觅食理论。油茶象优先选择大果实产卵。窝卵数越小,油茶象种内竞争越弱,幼体正常发育并成功脱果的概率越高,适合度增加。卵单产是油茶象应对寄主果实食物资源限制作用的一种“风险分散”行为适应策略。
中华卵索线虫线粒体基因组多态性分析
,,李神,吴运梅,王国秀
昆虫学报 , 2009,
Abstract: 为完善昆虫病原索科线虫线粒体基因组全序列数据库,更系统地研究其基因组特征和系统演化规律,进而为发挥该线虫生防潜力打下基础,我们开展了中华卵索线虫Ovomermissinensis线粒体全基因组的研究。该研究通过线粒体基因组滚环复制及酶切图谱,揭示了中华卵索线虫线粒体基因组具有种内遗传多态性,即群体中单体线虫具有独特的酶切条带,且条带累加之和变化范围较大,为16.5~24.5kb。为进一步了解线粒体基因组多态性特征及产生的分子机制,采用两步长PCR方法对2条代表性成虫线粒体基因组进行了测序及拼接,得其全长分别为18864和16777bp。对这2条序列的比对表明,线粒体基因组中位于ND2和ND4之间的可变区域,不仅基因排列顺序不同,且存在ND3基因重复现象,这是导致中华卵索线虫线粒体基因组呈现多态性的主要原因。通过对以上研究结果的分析及与GenBank中已有的6种索科线虫线粒体基因组序列进行比对,概括出其线粒体基因组基本特点:①线粒体基因排列顺序各不相同;②部分线虫线粒体基因存在重复现象,且重复次数不同;③线粒体基因组大小存在很大差异。
黄淮海平原雨养条件下冬小麦水分胁迫分析
刘明,武建军,,赵林,
地理科学进展 , 2010, DOI: 10.11820/dlkxjz.2010.04.006
Abstract: 雨养条件下的水分胁迫分析能够反映当地气候土壤条件下作物生长的水分环境对农作物生长的影响,可为农业干旱管理及灌溉策略的实施提供依据,减少农业干旱的发生.本文在阐述EPIC(EnvironmentalPolicyIntegratedClimateModel)作物生长模型水分胁迫计算过程的基础上,模拟黄淮海平原冬小麦在雨养条件下的生长过程,分析水分胁迫现象的时空分异.结果发现,研究区内自然降雨远不能满足冬小麦的正常生长,从水分胁迫现象发生时间上讲,雨养条件下在冬小麦生长期后段(5月中旬以后)水分胁迫现象较为严重,以5月下旬最为严重,重度水分胁迫发生频率高达48.2%;从区域分布上分析,冀鲁豫低洼平原区和山东丘陵农林区水分胁迫现象在整个研究时间段上均较为突出.
AZ31B镁合金挤压管材的内高压成形性能
,王小松,苑世剑,
金属学报 , 2007,
Abstract: 通过拉伸试验和胀形试验研究了不同温度下AZ31B镁合金挤压管材的成形性能。结果表明,随着温度的升高,管材的轴向拉伸成形性能有明显提高,但是其胀形性能并没有相应变化。这主要是因为挤压管材存在明显的各向异性,在环向的变形性能明显低于轴向。另外,采用分流模挤压的管材,在加热时焊缝成为最容易破裂的部位,出现了提前破裂,降低了管材的整体变形性能。
遮光对超级杂交稻叶片叶绿素含量的影响
刘科,,江龙彪,田小海,张运波
河南农业科学 , 2015,
Abstract:
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