共查询到20条相似文献，搜索用时 140 毫秒
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护岸工程(如水库护坡、堤防护坡、海岸防护等)在实际应用中,往往受到来自于波浪的作用力,波浪荷载是护岸结构的主要荷载之一,波浪对护岸的作用主要包括波浪对护岸结构的冲击压力、浮托力等。本论文基于FLUENT通过数值模拟的方法,研究模拟透水型护岸结构在波浪力作用下的受力。 相似文献
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介绍了一种就CSCW技术为基础的法院电子审判平台。平台采用集中分布方式为主结构,综合会话模型、会议模型、活动模型等,通过网络较好地实现了协同办案、协同审理、案件讨论等各种工作,提高了工作效率与透明度。 相似文献
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我们知道波动的产生首先需要一个处于平衡状态的介质,还需要有破坏介质平衡的扰动力和使介质恢复平衡的回复力,根据回复力的不同性质,对波浪的分类也很重要.回复力最重要的一种是重力,特别是对水自由表面的波浪,这种波浪成为表面重力波,第二种回复力是表面张力,这是由于水的表面具有表面张力的特性,水面一旦受到扰动,重力和表面张力力图使水面恢复到原来的平衡态,并形成波浪传播出去。 相似文献
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本文以在校大学生的胜任力为基本研究对象,运用冰山模型,探讨了大学生胜任力特有结构,研究了学校培养大学生胜任力的基本原则,结合实际工作的经验,探索出了顺利执行大学生胜任力的计划. 相似文献
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土地利用变化驱动力系统分析 总被引：168，自引：18，他引：168
该文应用系统论的观点和方法，对土地利用变化驱动力的整体性、层次性、动态变化和驱动力作用下的土地利用动态进行了深入分析，初步回答了土地利用变化的动力源、驱动力系统内部分力与合力的关系，以及驱动力与土地利用变化之间普遍存在的非线性反馈关系等问题，为土地利用变化动力学研究提供了新的思路。 相似文献
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Measuring forces applied by multi-cellular organisms is valuable in investigating biomechanics of their locomotion. Several technologies have been developed to measure such forces, for example, strain gauges, micro-machined sensors, and calibrated cantilevers. We introduce an innovative combination of techniques as a high throughput screening tool to assess forces applied by multiple genetic model organisms. First, we fabricated colored Polydimethylsiloxane (PDMS) micropillars where the color enhances contrast making it easier to detect and track pillar displacement driven by the organism. Second, we developed a semi-automated graphical user interface to analyze the images for pillar displacement, thus reducing the analysis time for each animal to minutes. The addition of color reduced the Young''s modulus of PDMS. Therefore, the dye-PDMS composite was characterized using Yeoh''s hyperelastic model and the pillars were calibrated using a silicon based force sensor. We used our device to measure forces exerted by wild type and mutant Caenorhabditis elegans moving on an agarose surface. Wild type C. elegans exert an average force of ∼1 μN on an individual pillar and a total average force of ∼7.68 μN. We show that the middle of C. elegans exerts more force than its extremities. We find that C. elegans mutants with defective body wall muscles apply significantly lower force on individual pillars, while mutants defective in sensing externally applied mechanical forces still apply the same average force per pillar compared to wild type animals. Average forces applied per pillar are independent of the length, diameter, or cuticle stiffness of the animal. We also used the device to measure, for the first time, forces applied by Drosophila melanogaster larvae. Peristaltic waves occurred at 0.4 Hz applying an average force of ∼1.58 μN on a single pillar. Our colored microfluidic device along with its displacement tracking software allows us to measure forces applied by multiple model organisms that crawl or slither to travel through their environment. 相似文献
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Sakshin Bunthawin Pikul Wanichapichart Adisorn Tuantranont Hans G. L. Coster 《Biomicrofluidics》2010,4(1)
An analysis has been made of the dielectrophoretic (DEP) forces acting on a spheroidal particle in a traveling alternating electric field. The traveling field can be generated by application of alternating current signals to an octapair electrode array arranged in phase quadrature sequence. The frequency dependent force can be resolved into two orthogonal forces that are determined by the real and the imaginary parts of the Clausius–Mossotti factor. The former is determined by the gradient in the electric field and directs the particle either toward or away from the tip of the electrodes in the electrode array. The force determined by the imaginary component is in a direction along the track of the octapair interdigitated electrode array. The DEP forces are related to the dielectric properties of the particle. Experiments were conducted to determine the DEP forces in such an electrode arrangement using yeast cells (Saccharomyces cervisiate TISTR 5088) with media of various conductivities. Experimental data are presented for both viable and nonviable cells. The dielectric properties so obtained were similar to those previously reported in literature using other DEP techniques. 相似文献
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选用混合模型研究受单一骨料约束的高干缩水泥浆的裂纹特性,在骨料中粘结力约束的影响通过应力传感器的试验测定。建立力学模型,将测量值作为计算值,对模型随时间变化的高干缩水泥浆的裂纹扩展情况进行线弹性断裂力学分析。力学模型的计算结果和试验结果是一致的。 相似文献
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运用软件CATIAV5R16中的PartDesign模块完成助力缸支架零件模型的建立;并利用Static Analyses模块,对助力缸支架进行受力分析,得出零件的应力分析云图。在应力云图的基础上,进一步进做疲劳断裂分析,为零件的合理设计提供了有价值的参考数据。 相似文献
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中小企业的技术创新面对复杂的支持和约束系统。本文设计了中小企业技术创机制的力学模型,解释了模型维度以及竞争压力、成长动力、推动力、拉力、障碍力这五种变量,分析了技术创新机制的主客体系统及其协调机制。此外,还利用模型就中小企业的技术创新提出了三点对策建议。 相似文献
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外戚在中国历史的政治舞台上扮演着重要的角色,其势力的膨胀则会对皇权统治构成严重的威胁。有明一代,宦官之害胜于汉唐,但外戚势力却得到有效的遏制。明代统治者为加强专制统治,吸取历史上外戚之害的教训,采取了诸多措施对外戚势力加以防范,使得明代外戚势力最为孱弱。 相似文献
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Using a magneto-mechanical solid-fluid numerical model for permanently magnetic artificial cilia, we show that the metachronal motion of symmetrically beating cilia establishes a net pressure gradient in the direction of the metachronal wave, which creates a unidirectional flow. The flow generated is characterised as a function of the cilia spacing, the length of the metachronal wave, and a dimensionless parameter that characterises the relative importance of the viscous forces over the elastic forces in the cilia. 相似文献