Papers by Keyword: Driving Force

Abstract: Mechanical principles are employed to analyze the working process of the modern agricultural circular bundling machine, the motion theorem of mass center of rigid body and the theorem of moment of momentum with respect to the centroid are used to give the relations between the driving force, feed roller diameter and angular speed and so on, the conclusions show the feasibility and technique in the design of the circular bundling machine.

Abstract: According to a series of hill area issues, such as big steep gradients, small and disperse plots, agricultural machinery climbing restriction and so on, a new 2-DOF bionic power-assisted legs mechanism driven by hydraulic is proposed. This paper states the design principle of the bionic legs mechanism and its application in agricultural machinery. A dynamic model is used to show how the hind leg assisted agricultural machinery is established, and then deduce the dynamics equation, and solve the inverse dynamics problems. The result shows that agricultural machinery movement along slope is steady with the help of the hind leg, and driving force of hydraulic cylinder changes is slightly without any distinct impact to other devices, the actuated project is feasible and the structure design is reasonable, and it can be used to research on intelligent control of bionic legs and hill area agricultural machinery.

Abstract: A dynamic mechanical model for actuating performance of piezoelectric material bonded on the surface of structures was established based on the second class of piezoelectric equation and continuum dynamics. Piezoelectric patches such as lead zironate titanate (PZT) to be used as an actuator were pasted on the surface of structures by bonding layers. An electrically and mechanically coupled model based on the piezoelectric equation and Newton's second law was set up and the dynamic equations of the coupled system were theoretically solved under the harmonic effect of the alternating voltage. Moreover, the effect of physical properties and the layer thickness of the PZT actuator were determined. The theoretical and experimental results showed that the proposed model was reasonable and precise to a certain extent.

Abstract: Predicting the driving force accurately is the key process to hydrate nucleating and growing of hydration reaction. The nucleating and growing process of hydrate is relevant to temperature, pressure and component of reactant, and the property of reaction tank and intermiscibility of reactant have notable effect on the formation process of hydrate with its nucleating position, the induction time, growth rate and hydration rate. However, the present driving force model of hydrate cannot predict nucleating area, induction time, growth rate and the reaction limit, and also can't explain the influence of some factors such as cooling rate, temperature disturbance and inlet way on the hydration reaction, it is uncertain of the process to gas hydrate nucleation. We introduced some driving force models, analyzed their merits and demerits, and looked into the distance of research direction to driving force in the future.

Abstract: A finite element model was established to describe the flow field and temperature field during the surface modification by electron beam in this paper. The driving forces of molten pool were considered in the mode. The flow of liquid metal was different between the inside and outside of the beam spot; the direction of the flow was along the surface to the specimen thickness. When the liquid metal was in the bottom of the pool, it flowed along the bottom to the pool edge. The largest flow velocity was 0.28m/s in the center of the beam spot, the minimum flow velocity was 0.11 m/s in the bottom of molten pool. The temperature of sample is uniform distribution, the temperature distribution show a gradient distribution in cross section.

Abstract: This study aims to analyze the effects and impacts of the main factors of urban built-up area expansion in Hangzhou, which can provide a reference to urban policy makers and urban planners on how to make a rational plan to develop the sustainable city. The study mapped Hangzhou urban built-up areas in different periods based multispectral scanner (MSS), thematic mapper (TM) and Enhanced Thematic Mapper-plus (ETM+). according the grey correlational degree analysis between urban built-up area expansion and the main social economic factors in Hangzhou, the results show that the sequence of the factors is non-agricultural population, on-campus college students, the industrial output value, GDP and the total investment in fixed assets, and it indicate that non-agricultural population play a key role to control the scale of urban space ，and the increasing number of on-campus college students promote Hangzhou urbanization.

Abstract: The liquid lift-up of directed combined trapezoid spray tray (CTST) was studied. The relationship between Liquid lifting capability of combined CTST and clear liquid height on the plate, F-factor based on tray hole was concluded. In single cap and combined several caps, the change of relative and absolute lift-up was also studied. The effect of F-factor to absolute elevating amount was determined by clear liquid height. On the condition of the higher or the lower clear liquid height, the influence of the F-factor to absolute lift-up was considerable. The relation between the pressure drop inside/outside of the bottom gap and liquid lift-up was studied.

Abstract: Anomalous expansion of stacking faults (SFs) induced in 4H-SiC under electronic excitations is driven by an electronic force and is achieved by enhanced glide of partial dislocations. An experimental attempt to separate the two physically different effects has been made by conducting photoluminescence (PL) mapping experiments which allowed simultaneous measurements of partial dislocation velocity and SF-originated PL intensity the latter of which is proposed to be related to the driving force for SF expansion through the density of free excitons planarly confined in the SF.

Abstract: The urban landscape pattern evolution and driving forces in SuZhou City in the past two decades were explored based on the landscape ecology theory and the ENVI 4.7 & Fragstats 3.3 technology, using the multi-source interpreted data of Landsat TM images in 1987,2005 and 2009, and Landsat ETM+ image in 2000. The indices chosen are the urban landscape overall constitution, average patch area, patch number, patch density, fractal dimension, contagion index, isolation index, fragment index, landscape diversity and evenness index. Taking the remote sensing as a platform to integrate and analyze the data, the driving forces are summarized together with the development of SuZhou City. This will supply the theory foundation and scientific basis for the land resources of reasonable planning and using, management, sustainable utilization, and the landscape pattern optimization configuration in SuZhou City. The results show that, the landscape pattern in Suzhou City changed greatly from 1987 to 2009. The construction land area increased, while the cultivated land, wood land and water body area decreased. The urban landscape contagion index and landscape fractal dimension were all increased, while the urban landscape diversity and evenness index were all decreased. The isolation index and fragment index of the construction land and cultivated land were small, this shows that the landscape pattern changed mainly by human factors. The population and economy growth together with industrialization and urbanization were main forces for the urban landscape pattern evolution in SuZhou City. The results can provide scientific evidence for ecological landscape design and urban development planning in other regions.

Abstract: The deployable structure of the ring truss have advantage properties, which can be used as an effective supporting structure of deployable antenna. The deployable experiment of ring truss antenna showed that there was asynchronous phenomenon at the course of the deployment. Dynamics theory including constraint equations and considering friction factor are built firstly. Then simulation is studied systematically for the deployment process of ring truss deployable antenna. At last, the conclusions are obtained that the friction insulted in tensile forces of the cable drive decrease and the asynchronous phenomenon in the process of the deployment. It will give some help to the design and manufacture of the ring truss antenna.