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排序方式: 共有246条查询结果,搜索用时 15 毫秒
101.
Dr. Tadeusz Kudra 《Drying Technology》2013,31(1-2):363-364
Abstract Revolving air flow was generated by oblique holes on air distribution board in a fluidized bed dryer. Such a revolving air flow shows a large scale velocity fluctuation in radial as well as tangential directions. This turbulent flow of air can fluidize the inert particles with superior performance than vibrated fluidized bed. The revolving fluidized bed is simpler in fabrication and easier in operation. For two types of inert particles tested, 4 mm glass beads and 4 mm × 5 mm Teflon cylindrical extrudates, the volumetric heat transfer coefficients were found to increase with the liquid feed flowrate and air flow velocity but decrease with the air inlet temperature, height of static bed, and liquid concentration. The revolving fluidized bed gives an increase of volumetric heat transfer coefficient by 1 kW/m3 K, and represents a 15–25% enhancement from ordinary fluidized bed operated at a bed height of 60 mm, bed diameter of 140 mm, superficial air flow velocity of 3.5 m/s, liquid feed (Soya milk) flowrate of 20 mL/min at a concentration of 6.7%, and a temperature ranges of 80–140°C using Teflon extrudates as inert particles. 相似文献
102.
Yong Jun Park 《Thin solid films》2010,519(5):1673-1676
A linear polarization selector was made from a three-section sculptured thin film deposited using an oblique angle deposition technique. In this device, the circular Bragg reflector with a left-handed helical structure was sandwiched in between two quarter-wave plates with opposite in-plane birefringence. Within the Bragg regime, the normal incident S-polarized light on this device was reflected, whereas the incident P-polarized light was transmitted through it. The microstructure of the linear polarization selector was also examined by scanning electron microscopy. 相似文献
103.
传统的电路模拟吸波材料设计只考虑正入射时的吸波性能,当入射角较大,尤其是大于30°时,雷达吸波器的吸波效果明显恶化。随着现代双站雷达探测技术的发展,雷达探测电磁波可能来自不同的空间方向,这就要求雷达吸波材料不仅在电磁波正入射时具有较高的吸波性能,在斜入射时同样实现良好的隐身特性。为此,该文提出了一种新型的宽带吸波材料。... 相似文献
104.
This paper presents a methodology to project the flux distribution from the image plane into the panels of any central receiver in Solar Power Tower plants. Since analytic functions derived from the convolution approach are conveniently defined on the image plane, its oblique projection solves the distorted spot found in actual receivers. Because of its accuracy describing the flux distribution due to rectangular focusing heliostats, we make use of the analytic function on the image plane by Collado et al. (1986). Based on the projection method, we have developed a computer code successfully confronted against PSA measurements and SolTrace software, either for flat plate or multi-panel cylindrical receivers. The validated model overcomes the computation time limitation associated to Monte Carlo technique, with a similar accuracy and even higher level of resolution. For each heliostat in a field, the spillage is computed besides the rest of optical losses; parallel projection is used for shading and blocking. The resulting optical performance tool generates the flux map caused by a whole field of heliostats. A multi-aiming strategy is investigated on the basis of the radius of the reflected beams, estimated from error cone angles. 相似文献
105.
As a solid-state welding process, Friction Stir Welding (FSW) offers a variety of advantages over traditional welding processes. Problems that are typically occurring due to the cooling of the liquid phase, such as solidification cracking and formation of porosity, generally do not occur in FSW. Nevertheless, as a result of suboptimal settings of the welding process parameters and certain uncontrollable conditions, FSWs are still associated with a number of specific flaws, e.g. root flaws and wormholes.Ultrasonic non-destructive testing and evaluation techniques (NDT&E) can be used for quality assessment of friction stir welded joints. In this paper, a novel approach for the detection of root flaws is proposed using an immersion ultrasonic testing method in oblique incidence and backscatter mode. The backscattered energy C-scan images obtained after an empirical positioning and proper time gating can be straightforwardly interpreted by direct comparison with typical ‘flaw’ patterns, allowing for identification and localization of the root flaws in the weld. The method is illustrated for FSW butt joints of the AlZnMgCu (7XXX series) alloy. 相似文献
106.
数字式电离层斜向探测系统 总被引:3,自引:1,他引:2
报告了在256型数字式测高仪和SSJX-1接收系统之间的斜向探测,收发两端采用BPM钟同步。本系统实现观测自动化,电离图数字化,尤其是采用高通数字滤波器对抑制外部干扰是很成功的。输出资料是电离图和信号能量~频率图。 相似文献
107.
108.
This paper investigates the current monitoring for effective fault diagnosis in induction motor (IM) by using random forest (RF) algorithms. A rotor bar breakage of IM does not derive in a catastrophic fault but its timely detection can avoid catastrophic consequences in the stator or prevent malfunctioning of those applications in which this sort of fault is the primary concern. Current-based fault signatures depend enormously on the IM power source and in the load connected to the motor. Hence, homogeneous sets of current signals were acquired through multiple experiments at particular loading torques and IM feedings from an experimental test bench in which incipient rotor severities were considered. Understanding the importance of each fault signature in relation to its diagnosis performance is an interesting matter. To this end, we propose a hybrid approach based on Simulated Annealing algorithm to conduct a global search over the computed feature set for feature selection purposes, which reduce the computational requirements of the diagnosis tool. Then, a novel Oblique RF classifier is used to build multivariate trees, which explicitly learn optimal split directions at internal nodes through penalized Ridge regression. This algorithm has been compared with other state-of-the-art classifiers through careful evaluation of performance measures not encountered in this field. 相似文献
109.
Yasuo Yamane Tadashi Hoshiai Hiroshi Tsuda Manabu Ohta Kaoru Katayama Hiroshi Ishikawa 《Multimedia Tools and Applications》2006,31(3):287-308
The Earth Mover’s Distance (EMD) and the quadratic-form distance (QFD) are representative distances used in similarity searches of images. Although the QFD greatly outperforms the EMD in speed, the EMD outperform the QFD in performance. The EMD, however, has almost no theoretical justification and requires high computation costs. We propose a feature space model we call a “multi-vector feature space based on pseudo-Euclidean space and an oblique basis (MVPO).” In MVPO, an object such as an image is represented by a vector set (roughly speaking, a solid) and the EMD is reinterpreted as the distance between vector sets while the QFD is reinterpreted as the distance between the centroids of vector sets. Therefore MVPO gives a common geometrical view to these distances. We hypothesized that in MVPO the entity of an image is represented by a vector set (solid) and geometrical reasoning is applicable to MVPO. Our hypothesis explains well that the EMD outperforms the QFD in performance because the centroid of a solid is the simplest approximation of it. Our hypothesis implies that the performance of the QFD should be good when solids are far apart but bad when they are close together. We conjectured that discriminability would decline—that is, dissimilar images would be judged to be similar—when the centroids of solids are very close. Our experiment supported this conjecture. And from our hypothesis we conjectured that by making an original solid simpler, we can make an approximation method that has better performance than the QFD and faster than the EMD. The results of our experiment with this method supported our conjecture and consequently our hypothesis.
相似文献
Hiroshi IshikawaEmail: |
110.