Papers by Keyword: Orthogonal Test

Abstract: A new manufacturing technology, external grind-hardening, is put forward and orthogonal tests are carried out with 3-level 3-factor aimming at 40Cr steel and 45 steel. A certain depth of Martensite layer is found on the hardened surfaces of both materials by metallographic observation and the hardness values meet the design requirement, which demonstrates the practicability of the new technology. Orthogonal analysis is proceeded successively for the acquirements of influencing pattern and significance of factors, and comparative study is carried on the hardening effect and feature for the both materials.

Abstract: With high optical transparency and electrical conductivity, ITO thin films were fabricated by DC magnetron sputtering. Series of research and exploration are presented on DC magnetron sputtering method for preparing ITO thin film. With substrate temperature of 60 °C, sputtering power of 200W,sputtering pressure of 1 mTorr, water pressure of 2×10-5Torr, the sheet resistance of the ITO conductive substrate is 53 Ω/□ and the transmittance is 83%.

Abstract: High strength fly ash ceramsite concrete has the advantages of low density, high compressive strength, but the brittleness is too large, limiting its application in engineering. In order to solve this problem, we used Carbon fiber in the orthogonal test. The results show that Carbon fiber can obviously improve the tension compression ratio of fly ash ceramisite concrete, improve the strength of fly ash ceramsite concrete brittleness.

Abstract: Direct drive volume control (DDVC) electro-hydraulic servo system has many advantages compared to the valve control system. However, its application scopes were restricted by its poor dynamic performance. To study the reason for the low dynamic response, mechanical model of DDVC electro-hydraulic servo system is established. Structure parameters influencing the dynamic performance are analyzed. To optimize the structure parameters, the methodology of orthogonal experiment is presented. The selection of factors and levels of the experiment and the choice of the evaluation index are also revealed. The proposed methodology is carried out by simulation software and an optimal configuration is obtained. The dynamic response of the DDVC system with the optimal parameters is simulated. The results show that the dynamic performances are improved. The cross-over frequencyincreases from 0.0046 rad/s to 0.0442 rad/s, and the rise time T_r decreases from 488.6s to 47.90s.

Abstract: The theory of orthogonal test provides a new design idea for the design of muffler with complicated structure. The second baffle plate position, outlet pipe perforation rate, connecting pipe diameter and perforation rate of a heavy vehicle exhaust muffler are chosen as the level factors. The sum of the transmission loss in the frequency range from 510Hz to 640Hz is chosen as the evaluation index. Based on the orthogonal test theory, GT-POWER software is used to analyze the evaluation index under different level factors. According to the orthogonal analysis table, optimization of the internal structure for the muffler is carried out. The optimized results show that attenuation performance of the optimized muffler in the optimized band is superior to the original muffler and the frequency bands allowing noise to pass through is significantly reduced.

Abstract: This paper introduce the H.264 encoding system, mp4 file format, based on which , propose a high efficient real time H.264 encoding system on Android . The system aims at transmitting high quality video under restricted environment. The system largely reduce the transmitted data but still maintain good quality .It can achieve 15fps at 1280P .We design a MFC program which use CAscyncsocket to receive the raw H.264 and use ffmpeg to decode it .You can add RTP or RSTP protocol , then you can use VLC player to decode it . Or you can implement a tiny http sever on Android phone, then you can use your browser to watch the video.

Abstract: The paper uses computational fluid dynamics software FLUENT to build a single-channel numerical simulation model of the mine ventilation gas Thermal Flow-Reversal Reactor (TFRR). Combining with the analysis of orthogonal test, the influences that four factors (Initial temperature distribution, Ventilation gas flow velocity, Volume fraction of methane, Exchange period) act on reactor performance is investigated. An optimal operation condition is proposed by the establishment of the priority sequence of these four factors.

Abstract: Based on the filter bank, the theory of multi-carrier modulation using Orthogonal Frequency Division Multiplexing (OFDM) and Modified Discrete Fourier Transform (MDFT) filter bank has been discussed and the detailed derivation process has been given. Following these discussions, the actual implementation of MDFT filter bank in multi-carrier modulation systems has been discussed, and then the comparison of their prototype functions, Peak to Average Power Ratio (PAPR) and Symbol Error Rate (SER) are drawn. Experimental results demonstrate that compared with the OFDM system, prototype functions of MDFT have obvious advantage in spectrum leakage. In terms of PAPR, they have similar performance. Whether using QPSK or 16QAM modulation, MDFT is superior to OFDM in symbol error rate as a whole and with increasing of filter length L, the advantage becomes more and more apparent.

Abstract: To study optimum inclusion process conditions for essential oil from perilla and Pericarpium Citri Reticulatae in Baokening granule,the utilization ratio of volatile and the inclusion rate were determined to evaluate process conditions, and the condition was optimized with orthogonal design by the liquid-phase method in aqueous solution. The experiment results showed that the optimum preparation conditions for inclusion were established as: oil: ß-CD was 1:8, and ratio of amount of water to ß –CD was 10. The inclusion temperature and time were at 40°C and for 180 min. The yield is high in such optimum process condition and the inclusion effect is good.

Abstract: The traction characteristics of lubricant is one of the important parameters of the dynamic performance of bearings design .This paper chose three significant factors affecting the traction coefficient：temperature、load and rotate speed. Test results showed that the traction coefficient under the high load is significantly higher than under low load from room temperature to 135 °C. After more than 135 °C, the traction coefficient under the low load is higher than under the high load. It illustrated that the grease was sensitive to temperature but it reflected high temperature stable performance.The optimum conditions were obtained by Design-Expert software optimization : temperature for 235°C、load for 2800.00N、rotate speed for 183.17r/min and in this time the traction coefficient is at 0.547 in this test. It shown that the grease fitted the low speed and heavy load equipment.