几种保存方法对中华哲水蚤和强壮箭虫体型的影响     

冯秋园  孙晓霞  任琳琳 《海洋科学》2014,38(4):20-26

选取5%的甲醛,–20℃冰冻和液氮为保存方法,以中国近海的2种优势浮游动物中华哲水蚤(Calanus sinicus)和强壮箭虫(Sagitta crassa)为研究对象,以体长、体宽和面积为体型参数,研究了上述几种保存方法在2个月的时间内对浮游动物体型的影响。研究结果显示,对于中华哲水蚤,甲醛保存2个月后,体长下降为原始体长的99.4%,体宽和面积都增加为107%;冰冻和液氮保存2个月后,体长分别增加为原始体长的101%和106.8%,体宽下降为90%和81.6%,面积下降为92.2%和88.8%。对于强壮箭虫,在甲醛、冰冻和液氮3种保存条件下,保存2个月后体长有所下降,分别为原始体长的92.8%,50.7%和48.4%。体宽和面积有所增加,体宽分别变为原始体宽的139.9%,159.4%和263.8%,面积分别变为原始面积的119%,97.8%和107%。综合分析发现,胶质类浮游动物在冰冻和液氮保存条件下,身体变形严重,因此用ZooScan测得的结果误差较大,相较而言,甲醛对胶质类浮游动物体型的影响较小;中华哲水蚤比强壮箭虫在各种保存条件下体型的变化要小;保存初期,浮游动物体型的变化幅度较大,后期趋于稳定;在3种保存条件下,中华哲水蚤和强壮箭虫体长的变化最稳定,其次是面积。对浮游动物的体型进行研究时,推荐使用甲醛保存条件下的体长或面积。  相似文献   

Application of otolith shape analysis for stock discrimination and species identification of five goby species （Perciformes： Gobiidae） in the northern Chinese coastal waters   总被引：1，自引：0，他引：1  

于鑫  曹亮  刘金虎  赵博  单秀娟  窦硕增 《中国海洋湖沼学报》2014,32(5):1060-1073

We tested the use of otolith shape analysis to discriminate between species and stocks of five goby species( Ctenotrypauchen chinensis, Odontamblyopus lacepedii, Amblychaeturichthys hexanema, Chaeturichthys stigmatias, and Acanthogobius hasta) found in northern Chinese coastal waters. The five species were well differentiated with high overall classification success using shape indices(83.7%), elliptic Fourier coefficients(98.6%), or the combination of both methods(94.9%). However, shape analysis alone was only moderately successful at discriminating among the four stocks(Liaodong Bay, LD; Bohai Bay, BH; Huanghe(Yellow) River estuary HRE, and Jiaozhou Bay, JZ stocks) of A. hasta(50%–54%) and C. stigmatias(65.7%–75.8%). For these two species, shape analysis was moderately successful at discriminating the HRE or JZ stocks from other stocks, but failed to effectively identify the LD and BH stocks. A large number of otoliths were misclassified between the HRE and JZ stocks, which are geographically well separated. The classification success for stock discrimination was higher using elliptic Fourier coefficients alone(70.2%) or in combination with shape indices(75.8%) than using only shape indices(65.7%) in C. stigmatias whereas there was little difference among the three methods for A. hasta. Our results supported the common belief that otolith shape analysis is generally more effective for interspecific identification than intraspecific discrimination. Moreover, compared with shape indices analysis, Fourier analysis improves classification success during inter- and intra-species discrimination by otolith shape analysis, although this did not necessarily always occur in all fish species.  相似文献   

语言经济原则的语用研究     

袁洪 《广东海洋大学学报》2014,(5):86-90

为提高语言交际效率,作者或发话人往往选择最精简的语言符号表达特定的思想,这就是语言经济原则,它作为规约语言使用的语用机制,对有关语用理论如会话含义理论、关联论和模因论等语用理论具有普遍约束力。  相似文献   

Effectiveness of superelastic bars for seismic rehabilitation of clay‐unit masonry walls     

Kshitij C. Shrestha  Yoshikazu Araki  Takuya Nagae  Toshihiro Omori  Yuji Sutou  Ryosuke Kainuma  Kiyohito Ishida 《地震工程与结构动力学》2013,42(5):725-741

This paper presents the results on shaking table tests of half‐scale brick walls performed to investigate the effectiveness of newly developed Cu–Al–Mn superelastic alloy (SEA) bars in retrofitting of historical masonry constructions. Problems associated with conventional steel reinforcing bars lie in degradation of stiffness and strength, or pinching phenomena, under cyclic loading, and presence of large residual cracks in structures during and after intense earthquakes. This paper attempts to resolve the problems by applying newly developed Cu–Al–Mn SEA bars, characterized by large recovery strain, low material cost, and high machinability, as partial replacements for steel bars. Sets of unreinforced, steel reinforced, and SEA‐reinforced specimens are subjected to scaled earthquake excitations in out‐of‐plane direction. Whereas steel‐reinforced specimens showed large residual inclinations, SEA‐reinforced specimens resulted in stable rocking response with slight residual inclinations. Corresponding nonlinear finite element (FE) models are developed to simulate the experimental observations. The FE models are further used to examine the sensitivity of the response with respect to the variations in experimental conditions. Both the experimental and numerical results demonstrate the superiority of Cu–Al–Mn SEA bars to conventional steel reinforcing bars in avoiding pinching phenomena. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

饱和软黏土中不同形状深水防沉板基础承载特性研究   总被引：4，自引：0，他引：4  

刘润  刘孟孟  杨树耕 《海洋学报》2016,38(3):131-144

防沉板基础是水下井口、管汇节点与管汇终端等的永久支撑结构,其承受的荷载具有明显的复杂性、非线性和不确定性,给防沉板基础的稳定性研究带来了巨大挑战。本文研究了在剪切强度随深度线性增长的不排水饱和软黏土中,相同用钢量条件下矩形、方形、六边形和圆形防沉板基础的承载特性。采用数值模拟方法确定了竖向荷载V、水平向荷载H(H_x、H_y)、弯矩荷载M(M_x、M_y)和扭矩荷载T联合作用下,防沉板基础在V-H、V-M、V-T、H_x-H_y、M_x-M_y、T-H和T-M荷载空间的地基承载力包络线,并建立了相应的拟合公式。研究表明,不同的基础形状对其承载力影响显著,当V较大时,适宜选用圆形基础;当H较为显著时,应选用矩形或方形基础;圆形、方形和矩形基础的抗弯特性分别适用于不同条件下M为主控荷载的情况;当T的影响不可忽视时,矩形或方形基础为首选形式,六边形和圆形基础次之。  相似文献   

Mapping ideas from cyberspace to realspace: visualizing the spatial context of keywords from web page search results   总被引：1，自引：0，他引：1  

Ming-Hsiang Tsou  Ick-Hoi Kim  Sarah Wandersee  Daniel Lusher  Li An  Brian Spitzberg 《International Journal of Digital Earth》2014,7(4):316-335

We introduce a new method for visualizing and analyzing information landscapes of ideas and events posted on public web pages through customized web-search engines and keywords. This research integrates GIScience and web-search engines to track and analyze public web pages and their web contents with associated spatial relationships. Web pages searched by clusters of keywords were mapped with real-world coordinates (by geolocating their Internet Protocol addresses). The resulting maps represent web information landscapes consisting of hundreds of populated web pages searched by selected keywords. By creating a Spatial Web Automatic Reasoning and Mapping System prototype, researchers can visualize the spread of web pages associated with specific keywords, concepts, ideas, or news over time and space. These maps may reveal important spatial relationships and spatial context associated with selected keywords. This approach may provide a new research direction for geographers to study the diffusion of human thought and ideas. A better understanding of the spatial and temporal dynamics of the ‘collective thinking of human beings’ over the Internet may help us understand various innovation diffusion processes, human behaviors, and social movements around the world.  相似文献   

条件随机场框架下基于随机森林的城市土地利用/覆盖遥感分类     

杨耘  徐丽  颜佩丽 《国土资源遥感》2014,(4)

针对"基于像素的条件随机场(conditional random fields,CRFs)模型能否在m级分辨率的多光谱遥感图像分类中表现良好"的问题,提出了集成图像的光谱、方向梯度直方图和多尺度多方向Texton纹理等多种线索的CRFs模型定义方法。利用上述特征,选择随机森林(random forests,RF)定义CRFs关联势函数;利用特征对比度加权的Potts函数定义CRFs交互势函数,并且建立了多标签的RF-CRFs模型;对该模型进行分项参数训练以及基于图割的α-膨胀算法推理;利用典型城区的Quick Bird多光谱图像进行模型的验证与精度评价。结果表明RF-CRFs模型的分类精度可达82.52%以上,比RF分类器的分类精度提高了3.35%。  相似文献   

Characterization of lunar dust and a synopsis of available lunar simulants     

Yang Liu  Lawrence A. Taylor 《Planetary and Space Science》2011,59(14):1769-1783

Understanding the formation and evolution of the soil and dust of the Moon addresses the fundamental question of the interactions of space with the surface of an airless body. The physical and chemical properties of the lunar dust, the <20 μm portion of lunar soil, are key properties necessary for studies of the toxicity and the electrostatic charging of the dust. These properties have been largely overlooked until recent years. Although chemical and physical studies of the <20 μm portion of lunar soil have been the topic of several studies, there is still need for further studies, primarily of the <1 μm particles. This paper presents a review of the studies of lunar dust that have been conducted to date. As many preparations for future exploration or science activities on the Moon require testing using lunar soil/dust simulants, we also include a brief review of past and current simulants.  相似文献   

Machine-learning-enabled discrete element method: Contact detection and resolution of irregular-shaped particles     

Zhengshou Lai  Qiushi Chen  Linchong Huang 《国际地质力学数值与分析法杂志》2022,46(1):113-140

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Three-dimensional quantitative analysis on granular particle shape using convolutional neural network     

Pin Zhang  Zhen-Yu Yin  Yin-Fu Jin 《国际地质力学数值与分析法杂志》2022,46(1):187-204

To identify all desired shape parameters of granular particles with less computational cost, this study proposes a three-dimensional convolutional neural network (3D-CNN) based model. Datasets are made of 100 ballast and 100 Fujian sand particles, and the shape parameters (i.e., aspect ratio, roundness, sphericity, and convexity) obtained by conventional methods are used to label all particles. For the model training, by feeding the slice images of particles into the model, the contour of particles is automatically extracted, thereby the shape parameters can be learned by the model. Thereafter, the model is applied to predict shape parameters of new particles as model testing. All results indicate the model trained based on slice images cut from three orthogonal planes presents the highest prediction accuracy with an error of less than 10%. Meanwhile, the accuracy for concave and angular particles can be guaranteed. The rotation-equivariant of the model is confirmed, in which the predicted values of shape parameters are roughly independent of orientations of the particle when cutting slice images. Superior to conventional methods, all desirable shape parameters can be obtained by one unified 3D-CNN model and its prediction is independent of particle complexity and the number of triangular facets, thus saving computation cost.  相似文献