Papers by Keyword: Particle

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Authors: Byung Nam Kim, Masanori Watanabe, Manabu Enoki, T. Kishi
Authors: Ju Young Yun, Yong Hyeon Shin, Kwang Hwa Chung
Abstract: In examining particulate deposits in the pipes within a chemical vapor deposition (CVD) system, vibration diagnostics is compared and studied against ultrasonic diagnostics. The latter method involves pulsing the outer wall of pipes with an ultrasonic sensor and analyzing the resulting echo to observe particulate deposits inside pipes. Vibration diagnostics examines the existence of particulate deposits by analyzing the difference in the frequencies generated when a vibrator is adhered to the outer wall of pipes. With ultrasonic diagnostics, good test results were obtained only when particulate deposits were attached to the inner wall of the pipes. After some time, however, particulate deposits were not detected properly, as the ultrasonic wave failed to cross the fine gaps created between the inner wall of the pipe and the deposits. In conclusion, the vibration diagnostics is being expected as the effective method in monitoring the particulate deposits inside pipes in the CVD system where the desired behavior is reduced frequency along with the the particulate deposits in comparison to the case where the pipe is clean.
Authors: Zheng Xu, Shou Ci Lu
Abstract: A new electrostatic dispersion device was designed to reduce the agglomeration of fine powder in the air. This device is using the repulse force between particles which charged the same charge to prevent the particles from reuniting. The effects of charge voltage, particle size, the distant between electrode, and moisture content on the dispersion degree of the powder are discussed. The invalidation time of the electrostatic dispersion is also highlighted in the paper. The results show that the electrostatic dispersion is an effective method for the fine powders in the air. The charge voltage is the most important parameter for the dispersion. Middle size particle got best dispersion. When the distance between the electrodes is 24cm, the dispersion degree reaches the maximum. The humidity of the powder not only affects the charge of the powder, but also affects the dispersion degree of the powder.
Authors: Yi Ping Zhang, Yi Yi Tao, Zuo Jiang
Abstract: The relationships among the n, ap , and f of the SiCp /Cu composite material produced by powder metallurgy and extrusion have been investigated. The cutting force F of this material is also discussed in this paper by the measuring of the three cutting factors of n, ap, and f, applying the dislocation theory and the electron microscope analysis of the cutting surface and sub-surface. The differences are analyzed between the SiCp/Cu composite materials, QSn6-6-3. H59-1and the copper cutting surface and the sub-surface. The forming of mechanism, the function of SiCp in the cutting process and the influence on the cutting surface quality are also analyzed. This research has shown: because the SiCp particles prevent the dislocation moving, the dislocation groups are formed on the SiC/Cu interface, and the stress concentration is produced, the typical brittle separation appears in the SiC/Cu composite material cutting process. In addition, the cutting force increases with the depth of cut and feed increasing and decreases while the cutting speed increases.
Authors: Liang Jing Jing, Rui Li, Yu Yu Li
Abstract: Heat transfer in wood particle controls the process of the pyrolysis. This paper makes a 2-D transient heat transfer model in cylindrical to predict the thermal behavior of wood particle in the process of fast pyrolysis. Wood anisotropy and thermophysical properties are considered in this model, as well as the influence of heat reaction on temperature distribution in wood particle. Based on the calculation of transient temperature in wood particle, and analysis of the temperature distribution during the process of wood fast pyrolysis at different time, this paper preliminarily discusses the optimization of parameters in wood particle fast pyrolysis. Keywords: pyrolysis, heat transfer, particle, wood
Authors: Yung Sheng Lai, Chun Wei Fu, Chuan Yi Pan, Rome Ming Wu
Abstract: This study proposed a new type of hydrocyclone. A rotating ring containing one pair of symmetric blades was attached to the overflow pipe. The momentum of the inlet fluid drove the ring/blades to rotate, and the rotating blades swept small-sized particles to the hydrocyclone wall to be discharged from underflow. This design can destroy circulation flow on hydrocyclone roof and make small-sized particles to be separated.
Authors: Li Jun Cao, Dong Yang Geng, Xiang Mei Yu
Abstract: At present, many Chinese cities are suffering from hazy weather. Blue sky and white cloud have become a luxury. The frequent occurrence of haze has imposed different levels of impacts on people’s livelihood and work, and people are paying continual attention to air quality. How to resolve haze problem has become an important concern of many scholars nowadays. This paper makes an analysis on the formation mechanism of haze as well as the impact and hazard of haze on people’s livelihood, and than proposes a long-term mechanism for the treatment measures to haze.
Authors: Yan Dong, Yang Zhou, Xue Lin Han, Wei Jie Gu
Abstract: Mg doped BaAl12O19:Mn2+ phosphor is one of the most efficient green phosphors for PDP. It is difficult to prepare the phosphor both have small particle size (< 3μm) and high luminescence. In the present work, a BaAl12O19:Mn2+ phosphor with small particle size was synthesized by the chemical co-precipitation method. Phase transformation and particle growth process during calcining process were investigated. The nucleation process was also discussed. The results show that, the phase transformation is complicated, the transition phases include BaCO3, γ-Al2O3, BaF2, BaAl2O4 and two phases contain Mn; The BaAl12O19 phase is formed from the reaction between BaAl2O4 phase and γ-Al2O3 phase, no a-Al2O3 phase appears during the entire process; The formation temperature of pure BaAl12O19 phase is 1200°C, which is lower than that in the high-temperature solid state reaction method. High efficiency BaAl12O19:Mn2+ phosphor with small particle size (< 2μm) and hexagonal flaky shape can be prepared by this method.
Authors: Peng Yuan Yang, Yu Hong Chen, Bin Chen
Abstract: The low-cost production and performance of 6061-aluminium alloy matrices reinforced with coated silicon carbide particulate has been studied. The micro-wave vacuum sintering was adopted to prepare the composite in order that the loss ignition is very small. The effect of copper coated silicon carbide has proved beneficial to interfacial bonding and improved the mechanical properties. Differences in the fracture characteristics of specimens containing coated and non-coated particles were observed. The particulates size has much influence on mechanical properties.
Authors: Zhen Yu Zhong
Abstract: It is proposed the method based on particle movement to simulate flow in this paper. The force on particles can be obtained from N-S equations, and the calculation error caused by particles’ simulation is discussed. Results show that the method is more effective through the example of flow field affected by the cube. The advantage of this method is to solve problems of multiphase flow and fluid-structure interaction.
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