Вип. 36
Постійний URI для цього зібранняhttps://repositary.knuba.edu.ua/handle/987654321/362
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33 результатів
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Документ Design and research on bending mould of high-strength plates(КНУБА, 2018) Zhou Huan; Hui WeidongCNC bending machine is a kind of molding pressure equipment, which is widely used in the process of sheet metal bending, it can press the sheet metal into different angles and different geometric shapes. Equipped with the corresponding industrial equipment, it can also achieve stretching, punching, such as corrugation processing technology. With the development of production technology, people become more and more pursue the quality. High-strength plate tensile strength and hardness is very high, When using a common mould for bending, would first destroy the mould and can't be bending. In this paper, the initial design of high-strength plate bending mold is carried out, the 3D model of each part of the mould is established, and the simulation analysis of the stress is carried out. The bending principle of the mould and the calculation formula of the bending force are introduced, has the very important economic significance for the reasonable selection of bending mould.Документ An improved CARI algorithm based on sliding window in MIMO-OFDM system(КНУБА, 2018) Zhang Hui; Xia Liling; Dong Rongwei; Wang HuihuiMIMO-OFDM is one of the core technologies in mobile communication system. As multicarrier modulation is adopted, the MIMO-OFDM system usually leads to high Peak-To-Average power ratio (PAPR), which can decrease the communication quality. The cross-antenna rotation and inversion (CARI) is an algorithm with better performance to reduce Peak-To-Average power ratio of MIMO-OFDM system. However, needing a large number of iterations is a shortage of CARI. The sub-optimal scheme of CARI – successive suboptimal CARI (SS-CARI) can reduce the number of iterations, but the PAPR reducing performance of it is lost largely. In view of this problem, a sub-optimal CARI method using sliding window to search for rotation and reverse combination is proposed in this paper. By using sliding window to search for the local optimal rotation and reverse combination, not only the overall traversal search can be avoided and the computational complexity of CARI algorithm can be reduced greatly, but also the PAPR reduction performance of SS-CARI can be improved. Simulation results show that a good trade-off between complexity of system and the PAPR reduction performance can be achieved by applying the proposed scheme.Документ Pipe line gravity heat pipe heat transfer numerical analysis research(КНУБА, 2018) Xu Zhipeng; Wang QisongGravity heat pipe is the most common type of heat pipe without core，it has the characteristics of simple structure, low cost, reliable work and high heat transfer efficiency. Waste heat recovery technology and comprehensive utilization of heat energy in various fields, the gravity heat pipe has reflected the unique superiority, according to the structure characteristics of the pipe line of gravity heat pipe, a mathematic model of the structure of the condenser. On the basis of mathematical model, through the preparation of the program C + + language, the numerical simulation study the communicating pipe type of gravity heat pipe heat transfer performance. A mathematical model is established according to the structural characteristics of the gravity heat pipe of the connected pipe row. Use FLUENT software for internal structure, to simulate the velocity vector according to the results of simulation analysis of pipeline of gravity heat pipe heat within the rationality of the steam and condensate return movement trend.Документ Mechanical design of small vertical axis wind turbine(КНУБА, 2018) Wang BinA new type of vertical shaft wind generator has a mechanical structure design, which can adjust the installation Angle of the wind blade according to the wind speed. When the wind force is large, the speed of the generator is higher than the rated speed. The blade Angle is adjusted by controlling the front and back movement of the electric push rod, so that the speed of the vertical shaft wind generator can be reduced to the rated speed. In this way, the stopping and fault of the wind generator caused by excessive speed can be avoided. At the same time, the braking system of the vertical shaft wind generator is designed, and the mechanical braking system is adopted.Документ An electronic device integrating linear and non-linear metering(КНУБА, 2018) Sun Lixiang; Wang ChunmoThis paper designs an intelligent electronic metering device for the post office. Programs realize the non-linear relationship between the price and the weight of letters. The whole system is mainly composed of hardware and software. The hardware design uses STC89C52 MCU as the core control device of the system. MPX4115 pressure sensor collects the weight data and sends the output analog data to ADC0832. The converted digital data will be sent to the single chip microcomputer for data processing and the digital tube will display the data. The system is equipped with a matrix keyboard and four independent keys, which are used to select the delivery location (local port or foreign port), express delivery or letter type (ordinary or registered letter) and screen clearing function. The matrix keyboard is used to input the unit price. The prominent feature of this design is that it can not only realize the weighing of the weight and price of general merchandise in a linear relationship, but also realize the weighing of the weight and price in a non-linear relationship such as express delivery or letter. The design of the device can improve the deficiency of the electronic weighing system in application and has certain practical significance.Документ Development of the temperature and humidity intelligent control system for fig orchard based on rfid technology(КНУБА, 2018) Luo WenhuaFor increasing the fig production and quality, and saving the labor cost, a kind of management fig garden intelligent system is designed combining the research on the fig tree cultivation situation and growth period. In this system the RFID tags which are equipped with sensors are installed on side of fig trees and will sense and save the temperature and humidity in Real Time mode. Data will be sent to a small Server trough the LAN from the Readers of RFIDS which are installed in different parts of the orchard. The Server will save the data and analyze them based on its software. If the humidity or temperature is not in a good condition, a tractor equipped with watering and poison tank, air conditioner and humidifier will be activated and sent to the tree. The intelligent gardening software system include tree guarding software(TGS) and path finding software(PFS). The TGS is installed on the Server, and investigates all data of each tree. If any tree needs watering or temperature change, it will indicate the amount and the type of the requirement. The server will send the information to the interfacing circuit and the tractor will receive the information, head to the tree and take the necessary steps. The PFS is also installed on the Server and receives the identification code of the nearest tag via the Reader which is connected to Server for recognize tractor coordinates. Then modified route base on inter database and identification code, finally move to the goal tree.Документ Intelligent brake design based on RBR and CBR hybrid reasoning(КНУБА, 2018) Hui Weidong; Zhou Huan; Gu QiFor intelligent design of a brake, different knowledge should be obtained effectively from the huge design knowledge sources.To improve efficiency of case-based reasoning in design of brake products and accurately reason the required optimal design proposal, by combining design characteristics of the brake, this paper proposes one CBR-RBR hybrid reasoning method by studying and analyzing brake design flow and field knowledge,by combining the phase hierarchical structure of product design, different reasoning mechanisms are used in the design of the brake proposal and specific parameterized design. The CBR is used to reason the design of brake proposal, structural type of specific type and selection of general deployment mode. RBR is used to reason the case adaptions of main structures, size parameters, structural models and materials used. The general structure design of the brake is used to explain the whole process.Документ A 12-bit -channel pipeline ADC WITH 81 DB SFDR in 250 MS/s single0.13 UM CMOS(КНУБА, 2018) Gu Jianhua; Yan Guojun; Ben NengjunA 12bit 250-MS/s pipeline ADC is presented and fabricated in 0.13um CMOS process. A power efficient bootstrap switch with a buffer is proposed for high speed considerations. It utilizes a source follower to insulate the residue amplifier and the large capacitor in the bootstrap switch. Techniques of lightening load capacitance of each stage are proposed to speed up the corresponding residue amplifiers (RA). A clock generator and optimized timing are proposed to achieve low jitter and improve sampling linearity by saving more time for the input switch. The reference buffer and clock buffer are both fully integrated. The signal-to-distortion-and-noise-ratio (SNDR) is evaluated adopting a proper scheme and verified by the measured results. The measured SNDR is 63 dB and spurious free dynamic range (SFDR) is 81dB with 39 MHz. The core area is 2 mm2 and the ADC consumes 160 mW at 1.3V.Документ The investigation of eutectic nucleation and growth mechanism of Al-Si alloy(КНУБА, 2018) Anzhu Chen; Pengfei ZhouAl-Si binary eutectic transformation, solidification occurred in the late eutectic (cell) crystal nucleation, eutectic nucleation and growth are a direct impact on formation of the defects of organizations (such as: shrinkage, thermal cracking, etc.) and the distribution of impurities elements and compounds, and so on .In this paper, analysis the microstructure of the alloy with modification by Sr, also thermal analysis was used to measure the unmodified alloys, EBSD was used to analysis the alloy with different status. The results showed that: The EBSD technique, whether or not modification, we observed that the eutectic nucleation on the primary dendrite and heterogeneity in inter-dendrites exist, and Sr has a significant effect on the primary α-Al, the primary α-Al phase in the AlSi10.5 alloy modified by 0.04% Al-10 wt. % Sr is more rounded and the size is much smaller than unmodified alloy. Fe has a great influence on the nucleation of eutectic Si.Документ Research and design of raw silk evenness detector based on CCD image sensor(КНУБА, 2018) Hu YucaiIn this paper, a dynamic measurement system of raw silk evenness based on machine vision is introduced. When the raw silk is moving at a certain speed by a drive device, the raw silk images are continuously captured by image acquisition system including a Charge Coupled Device (CCD) line sensor, a telecentric lens, a light source. To extract the main body of the raw silk accurately, the raw silk images are processed sequentially with threshold segmentation, morphological opening operation. And then the raw silk evenness is characterized by calculating the coefficient of variation (CV value) of diameter. Different image processing methods are discussed. When compared with the existing measurement and assessment of raw silk evenness, such as blackboard manual eye inspection and capacitance-detecting technology, the measurement method using machine vision has following characteristics. Firstly, because the image capture equipment is linear CCD with high resolution, the dynamical measurement of raw silk evenness can be realized with high speed. Secondly, the telecentric lens is adopted in the designed raw silk evenness measurement, which can eliminate the influence of the jitter of raw silk along the optical axis when image capturing. Finally, the high quality raw silk image can provide the information about raw silk after image threshold segmentation and morphology operation.