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1.
Under the action of lateral forces and vertical loads, the connection of reinforced concrete slab-column structure will not only transfer significant shear forces, but also unbalanced moment. As to the edge slab-column connection, even if there is no later force, it will also transfer unbalanced moment due to the asymmetry. Currently, most tests and studies focus on interior connections, but there are few tests or studies on edge slab-column connections. A relatively new type of shear reinforcement named shear-stud reinforcement was applied in edge column-slab connections and study on the seismic behavior of these connections was conducted. Tests and finite element analysis of three full-scale reinforced concrete edge slab-column connections subjected to gravity and unbalanced moment were completed in this paper, and main conclusions were as following: the bearing capacity, deformation capacity and seismic behavior of connections reinforced with shear-stud reinforcement are improved; deformation of specimens reinforced with shear-stud reinforcement could meet requirements of current codes; the performance of energy dissipating is as good as the common connections, and has reached the medium ductility level. 相似文献
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Based on the investigation of engaging points' displacement of gear pump with three idle gears ,the radial components of instantaneous hydraulic pressure and the engaging force of the compound pump are analyzed .The research comes to the conclusions that the instantaneous radial forces acting on center and inner gears can be balanced so long as the center gear has triple times tooth ,and the idle gear of even tooth makes less radial hydraulic pulsation than those of odd ones. [WT5HZ] 相似文献
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Ice shedding on transmission lines results in longitudinal unbalanced forces on adjacent transmission towers,which significantly threaten the safety of transmission lines.The methodology of ice shedding simulation on transmission lines is developed by using the finite element method and validated by comparing the simulation results with those obtained from the model scale experiments done by previous researchers.The responses of the tower line system induced by simultaneous ice shedding on the conductor and ground wire are analyzed.The developed methodology is then applied to study ice shedding considering unzipping effect,in which the influence of the velocity of ice shedding on the responses is investigated.Results from this study show that the longitudinal unbalanced forces induced by simultaneous ice shedding from the ground wire are greater than those from the conductor under similar condition.During the analysis of ice shedding considering unzipping effect,the slower the velocity of ice shedding is,the closer the responses are to those resulting from static unloading;and the faster the velocity of ice shedding is,the closer the responses are to those resulting from simultaneous ice shedding. 相似文献
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In this paper the common submersible pump and the foul water submersible pump were compared with the submersible sand pump. Then, the principle and structure features of the submersible sand pump were introduced. The hydraulic pattern of submersible sand pump was designed according to two kinds of fluid theory. There is an air room at submersible sand pump added. The motor axle of submersible sand pump was extended from the air room. Inside the motor there is a small reservoir and the drop of water can be collected. The working condition of submersible sand pump was improved. The submersible sand pump can work longer time. 相似文献
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Sun Dongye Qin Datong Yang Yalian 《保鲜与加工》1998,(4):1-6
Based on the kinematic and kinetic characteristics, the friction model of a metal pushing V(belt continuously variable transmission (CVT) is established in this paper. The relation between applied forces and speed ratio as well as transmitted torque is analysed. The coputational formulas on the tension forces of steel ring and compression forces between metal blocks are derived. The theoretical bases for designing a metal pushing V belt CVT equipment and its control system are provided. 相似文献
6.
Do Geographic Concentration and Vertically Related Variety Foster Firm Productivity? Micro‐Evidence from Italy 
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下载免费PDF全文 Using a large unbalanced panel dataset of more than 12,000 Italian manufacturing firms for the period 1999–2007, this paper investigates the role of geographic concentration and related variety on firms' total factor productivity (TFP). The main idea is that diversification—captured by a measure of vertically related variety—promotes firm innovativeness and, consequently, productivity, but when the technology has been consolidated, firms join specialized clusters that enhance efficiency. Our results suggest that the effect on firms' TFP of geographic concentration is stronger than that of related variety. We also confirm previous findings on the relevance of agglomeration forces for small firms compared with medium and large firms, where these agglomerative forces do not seem to influence TFP. 相似文献
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An image edge detection algorithm in fuzzy domain is proposed, which combines adaptive fuzzy enhancement and multi direction fuzzy morphology to detect the edges of fuzzy image. The adaptive fuzzy enhancement method enhances the fuzzy image within blocks with sliding windows to avoid losses of the real edges resulting from enhancing with single threshold for the whole image and lead strong adaptive ability to image region variance. The multi direction fuzzy mathematical morphology operates on the enhanced fuzzy image with structure elements of multiple different directions to extract the real edges with directionality and restrain non directional noise. Experiments show the algorithm can detect fuzzy image edge effectively with strong antinoise ability. 相似文献
8.
In this paper the low-temperature hydraulic floor heating system of a residence in Chongqing was tested. The influence of this system and the heat pump air conditioning system on indoor thermal comfort and operation cost was analyzed and compared. The effect of heat dissipation by radiation and convention of the floor was analyzed. It shows the feasibility and advantage of floor heating system in Yangtse River Region. 相似文献
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我国冷链物流发展还比较落后且发展不平衡,现代化冷链物流体系的建成是一个长期的艰巨的任务。果蔬预冷是冷链物流的重要环节,可以显著降低流通过程中的损耗,延长运输期和货架期。相对于贮藏设备及流通设备,预冷投资小、效果显著。表明我国现阶段应以预冷为出发点,降低果蔬流通成本,推动我国现代冷链物流的发展。 相似文献
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Earthquake induced dynamic axial force in reinforced concrete (RC) bridge bent columns will not only change the yield strength of the columns but also change their stiffness, which is seldom considered by the common lumped plasticity line model. Based on the fiber element model results that taking into account the influence of dynamic axial force on strength and stiffness simultaneously, the axial force stiffness interaction effect on the seismic responses of RC double column bridges was analyzed. The results show that, axial force stiffness interaction has a large effect on the seismic responses of the double column bridge in the elastic range, and it does not alter the ultimate capacity of the columns. Since the stiffness of the columns under compression and tension dynamic axial forces offset each other, the global displacement of bridge bent with equal columns is relatively unaffected by the axial force stiffness interaction, however, the differences of the column member forces are manifest. For the short column controls the global stiffness, the axial force stiffness interaction has significant influences on both the global displacement and member force responses. The influences become larger as the irregularity of the bridge bent increases, so the interaction between axial force and member stiffness should be sufficiently considered in seismic analyses. 相似文献
12.
The constitution, design ideas and working principles of the DDC experimental system for testing dynamic tensile stress of outside body cell using membrane variable stress wave are discussed in detail. A new design measure is put forward, i.e. using airtight liquid for transferring pressure, and a space mechanism which is made up of two moveable linking axes and controlled by DDC for producing dynamic tensile stress with variable stress wave. The space mechanism is made up of two moveable linking axes, the first axis is controlled by an alternative current servo system, at the same time it drives the modulating modulating disc, and its rotation velocity is uniform and adjustable, so the rotating velocity of the disc can be controlled. Second, the hydraulic pressure worktable is driven by step electric motor. By dynamically changing the relative position of the modulating disc and the worktable, the journey of the piston in hydraulic pressure vat can be changed accordingly. The resultant motion of the modulating disc rotation and the radial direction relative movement of the piston can create liquid pressure with variable frequency and amplitude range, and the pressure can be changed into membrane tensile stress with variable frequency and pressure amplitude range using pressure fine tuning, and muhi-path disporting pressure. The system is proved to be simple, reliable, economic and controlled expediently by the experiment conducted. 相似文献
13.
四级种子生产程序及其应用 总被引：3，自引：5，他引：3
我国长期沿用的农作物良种繁育方法“三圃制”，存在许多弊端，已不适应农业发展形势的需要。在多年农作物良种繁育实践中研究总结出的“四级种子生产程序”，能有效地保持优良品种纯度和种性。节约种源，减少世代，有利于实现种子标准化，延长使用年限。经济简便，解放了生产力。使育、繁、推一体化，形成了合力。该方法以现代遗传学作为理论基础。几年来，已迅速在河南省大部分地市推广应用，效益显著。 相似文献
14.
The hydraulic loading and wet/dry(W/D) ratio,which are two important indexes in the constructed rapid infiltration,can affect the removal effect.Presently,the domestic experimental reports about the hydraulic loading and(W/D) ratio aiming at the Three-Gorges Reservoir Region is rather scarce.This article studies some pertinent hydraulic loadings and W/D ratios suitable for the Region.The authors emphatically research the effect of CRI treating COD,TN and TP in the sewage under four hydraulic loadings and three different W/D ratios.It is suggested that when the temperature is ascending,the W/D ratio can be risen to some extent.The variations of loading and ratio can affect the COD,TP removal effect a little,but affect the TN removal effect much.The experimental conclusions can provide evidence to the application of constructed rapid infiltration in the Three-Gorges Reservoir Region. 相似文献
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In this paper, the conditions of air - cooled heat pump operation indoors in winter are analyzed. The corresponding performance of air - cooled heat pump operation is gained. The ventilation condition for stable operation of air - cooled heat pump indoors in winter is found. At the same time, the experimental results are approved by the actual operation effect. 相似文献
17.
Wang Tiesun Yang Yang 《保鲜与加工》1988,(2)
This paper introduces the comprehensive hydraulic testing set for many kinds of hydraulic elements with hydraulic drive, hydraulic regulation and hydraulic loading. It has rational structure compact arrangement, reliable characteristics and advanced technique. In order to reduce the energy loss in the hydraulic system of the testing set, 1 ad sensing control is used. The static and dynamic characteristics of the load sensing system are analysed with the method of numeral simulation on computer. the testing witk load sensing control results show energy may be saved obviously and the heat load in hydraulic system may be reduced effectively, then testing quality is improved and the volume cf oil case is lessened. The lead sensing valve design is satisfied with simplifying structure so that it may be used reliably for the fixed flow hydraulic system of the testing set or other machines. 相似文献
18.
《Soil Technology》1992,5(2):143-149
When Richard's flow equation was solved numerically two parameter estimation procedures were assessed for their applicability in the estimation of parameters of soil hydraulic characteristics, the water retention and hydraulic conductivity functions, and saturated hydraulic conductivity. The estimation procedures assessed were Taylor expansion and Marquardt (1963). The model simulated soil water content and pressure head profiles, obtained with the optimized estimates for the parameters from either method, agreed close with the corresponding measured profiles. Similar trends were observed for the water retention curve. The unsaturated hydraulic conductivities calculated, using the measured values in water content and pressure head agreed with those obtained using the established hydraulic conductivity functions. The results show that the techniques developed in this study were satisfactory to predict sufficiently accurate the hydraulic characteristics required to describe unsaturated flow of water in soil. The techniques appear promising, becuase the auxilliary information, soil water content, required for the estimation of hydraulic characteristics was minimal and relatively easy to collect. 相似文献
19.
In order to get the wave loads on pile groups with slab merged in water, an engineering approach was proposed. Three coefficients in terms of slab effect were discussed and a time -domain analysis of wave forces acting on piles was conducted. Wave diffraction from a slab was obtained by the potential theory and eigenfunction expansion method, while wave loads on piles were evaluated by Morison formula. The wave force on pile obtained by the proposed method and the numerical simulation are in good agreement, which shows a good reliability of the proposed method. The result shows that, owing to the size of slabs, there exist some differences in the changing rule of slab effect varying with the submerged depth. The resultant force decreases with the rise of incident wave number, and the changing trend of its acting point appears an inflection point at some wave number. The minimum force acting on piles lies in the meeting-wave side of the slab, while the maximum one arises at the back side or in the scope of 30 degrees between the axis of slab, which is perpendicular to the incident wave, and the back side. The presence of slab causes the deflexion and phase difference of inline force. Meanwhile, the grouping piles coefficient can be taken as 0.7. 相似文献
20.
基于极限平衡理论,以砂土边坡为研究对象,推导了渗流和地震存在时拟静力法和拟动力法边坡安全系数的计算表达式。通过程序求解,与已有算例对比表明,计算结果基本一致,验证了2种方法解析式的合理性。参数分析表明,水位越高,边坡失稳越严重,水力梯度与安全系数基本为线性关系。渗流方向向下时,稳定性随水力梯度的增加而增大;渗流方向向上时,变化规律相反。水平地震加速度系数对稳定性的影响剧烈,竖向地震加速度系数对稳定性影响较小,简化计算可以忽略不计。最终得出拟静力法的解析式,简单、实用,而拟动力法则可以更为全面地考察砂土边坡稳定性随时间变化的特点。 相似文献