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Micro-vibration response of satellites on orbit is different from that on ground test, and it is necessary to acquire micro-vibration response on orbit by simulation analysis using ground test data. In this paper, development and ...
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Micro-vibration response of satellites on orbit is different from that on ground test, and it is necessary to acquire micro-vibration response on orbit by simulation analysis using ground test data. In this paper, development and study of micro-vibration simulation analysis for small satellites is introduced, which uses the characteristic data of micro-vibration disturbance sources as analysis input, acquires displacements and angular displacements at key position by structural analysis, following by image quality influence analysis. The small satellite's micro-vibration simulation analysis system includes the module of micro-vibration test data analysis, the module of micro-vibration FE modeling and analysis, the module of micro-vibration calculation data analysis, and the module of imaging quality influence analysis induced by micro-vibration. The system can directly take micro-vibration acceleration test data, force and moment test data or angular displacement test data at key position into account, so it uses varieties of micro-vibration test data effectively,and improve reliability of micro-vibration analysis.
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In this paper numerical simulations were conducted to analyze the effects of design parameters and distribution of balancing-hole on the axial-force of a partial emission pump. The studied pump is a single stage pump with a Barske...
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In this paper numerical simulations were conducted to analyze the effects of design parameters and distribution of balancing-hole on the axial-force of a partial emission pump. The studied pump is a single stage pump with a Barske style impeller. Based on the original impeller, we designed 7 pumps with different balancing-hole diameters and the partial emission pump equipped with different impellers were simulated employing the commercial computational fluid dynamics (CFD) software Fluent 12.1 to solve the Navier-Stokes equations for three-dimensional steady flow. A sensitivity analysis of the numerical model was performed with the purpose of balancing the contradiction of numerical accuracy and the cost of calculation. The results showed that, with increasing of the capacity, the axial force varies little. The diameter of the inner balancing-hole plays a dominant role of reducing axial-force of partial emission pump, the axial-force decreases with increasing of inner balancing-hole diameter on the whole range of operation, the axial-force of impeller without inner balancing-hole is approximately 3 times larger than that of impeller with inner balancing-hole. While the diameter of outer balancing-hole has a reverse effects compared with that of inner balancing-hole. With increasing of outer balancing-hole, the axial force increases accordingly.
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This work present a linear generalized predictive controller (GPC) to stabilize the attitude of the quadrotor. Without the conventional linearization method or identification online, a dynamic compensation linearization approach w...
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This work present a linear generalized predictive controller (GPC) to stabilize the attitude of the quadrotor. Without the conventional linearization method or identification online, a dynamic compensation linearization approach with extended state observer (ESO) was provided to linearize the attitude dynamic. Then, a generalized predictive controller based on a linear nominal model was designed for the attitude of the quadrotor. The controller in this study not only reduces the computer process, but also increases the robustness of the system. The simulation results indicate the good performance of the controller applying to the quadrotor attitude stabilization.
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An explicit nonlinear analysis was implemented to calculate buckling load and stress distribution, based on the Abaqus/Explicit computer program. According to the numerically obtained results, we can optimize the structure of the ...
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An explicit nonlinear analysis was implemented to calculate buckling load and stress distribution, based on the Abaqus/Explicit computer program. According to the numerically obtained results, we can optimize the structure of the PET bottle in order to increase the buckling load. Moreover, according to the stress contour of PET bottle obtained by Abaqus, plastic distribution of PET bottle was optimized in order to improve the PET material efficiency and reduce the weight of PET bottle, and which provides a new design ideas for lightweight design of the PET bottle.
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Ultrafine e grain amorphous silicon nitride (Si3N4) powders were produced via direct nitridation process of silicon powders in transport bed. The properties of the nitridation products, such as morphology, phase composition, chemi...
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Ultrafine e grain amorphous silicon nitride (Si3N4) powders were produced via direct nitridation process of silicon powders in transport bed. The properties of the nitridation products, such as morphology, phase composition, chemical composition and structure, were examined using standard characterization techniques (SEM, XRD, FTIR, etc). The experimental results showed, in the case of silicon powders with particle size of 2.7μm, the conversion rate of silicon was 53.4% at reaction temperature of 1380℃ and reaction time of 2.7minutes, and the products mainly comprised amorphous silicon nitride powders.
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摘要 :
Ultrafine e grain amorphous silicon nitride (Si3N4) powders were produced via direct nitridation process of silicon powders in transport bed. The properties of the nitridation products, such as morphology, phase composition, chemi...
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Ultrafine e grain amorphous silicon nitride (Si3N4) powders were produced via direct nitridation process of silicon powders in transport bed. The properties of the nitridation products, such as morphology, phase composition, chemical composition and structure, were examined using standard characterization techniques (SEM, XRD, FTIR, etc). The experimental results showed, in the case of silicon powders with particle size of 2.7μm, the conversion rate of silicon was 53.4% at reaction temperature of 1380℃ and reaction time of 2.7minutes, and the products mainly comprised amorphous silicon nitride powders.
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The lack of logistics demand and the inefficient logistics operation of the society have become the main problem which constrains the development of China logistics, at the same time; the development of the logistics directly affe...
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The lack of logistics demand and the inefficient logistics operation of the society have become the main problem which constrains the development of China logistics, at the same time; the development of the logistics directly affects the national economy. Through the correlation analysis of logistics demand factor and national economy, the link will be obvious, thereby developing suggestions will be proposed.
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The lack of logistics demand and the inefficient logistics operation of the society have become the main problem which constrains the development of China logistics, at the same time; the development of the logistics directly affe...
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The lack of logistics demand and the inefficient logistics operation of the society have become the main problem which constrains the development of China logistics, at the same time; the development of the logistics directly affects the national economy. Through the correlation analysis of logistics demand factor and national economy, the link will be obvious, thereby developing suggestions will be proposed.
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According to the characteristics of strong theoretical, abstract concepts and fast technological update in the course "The Principle and Application of PLC", a series of exploration measures are improved in the content of classroo...
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According to the characteristics of strong theoretical, abstract concepts and fast technological update in the course "The Principle and Application of PLC", a series of exploration measures are improved in the content of classroom teaching, experimental training teaching, school-enterprise cooperation, school-enterprise training, and so on. They can improve students' interests in learning, bring up the scientific thinking and creative abilities, so that improve their overall qualities.
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It is necessary, for a modern enterprise, to solve the urgent problem that how to effectively integrate enterprise existing resources and increase overall operational efficiency. In this paper, a tally Devanning/Container Loading ...
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It is necessary, for a modern enterprise, to solve the urgent problem that how to effectively integrate enterprise existing resources and increase overall operational efficiency. In this paper, a tally Devanning/Container Loading business system based on the lightweight framework of J2EE(Spring + Hibernate + Struts) was implemented, according to the detailed analysis of business requirements and goals achievement. Firstly, this paper constructed framework for Devanning/Container Loading Management System. Secondly, it achieved the following aims, such as the acceptance and distribution of plan for devanning and dontainer loading, write-offs, a license management, statistics management and rights management. Thirdly, it established a customeroriented data interface and a variety of security policies. Finally, the Devanning/Container Loading management system has been integrated into the entire enterprise management information system. The system effectively integrated the existing application resources of enterprise and reduced the degree of coupling between system modules. It achieved the aim that optimization approach can be used to deal with the complex Devanning/Container Loading business and the operation efficiency of enterprise was vastly improved.
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