Synchronous-frame current control of multiphase synchronous motor under asymmetric fault condition due to open phases

In this paper, a synchronous-frame current controller of a multiphase synchronous motor with open phases is proposed. The proposed method cannot only possess the superiority of a linear controller over the conventional hysteresis-type current controller but it also enables the current to be regulated without a steady-state error. The key idea is that all the harmonics of the current and voltage, which can still contribute to the torque positively, can be equivalently represented as dc components even under asymmetric fault conditions. Throughout this paper, a five-phase synchronous motor with one open phase is used as a practical example, and the basic concepts can be easily extended into an n-phase ac motor with multiple open phases, which has the arbitrary number or configuration of the remaining healthy phases. Experimental results prove the validity of the proposed modeling and control algorithm.     

Preparation of epitaxially grown LaSrCoO3 thin films on SrTiO3(100) substrates by the dipping-pyrolysis process

LaSrCoO₃ thin films were spin-coated onto SrTiO₃(100) substrates by the dipping-pyrolysis process. X-ray diffraction -2 scans and X-ray diffraction scans were used to determine the crystallinity and in-plane alignment behavior of the films. The X-ray diffraction pattern shows the film obtained by annealing at 800°C was highly oriented. The X-ray diffraction pole-figure analysis and reciprocal-space mapping (-2 scans) of the resulting film showed that the film comprising the pseudocubic phase had an epitaxial relationship with the SrTiO₃ substrate.     

Loosening mechanism of threaded fastener for complex structures

Journal of Mechanical Science and Technology - Threaded fasteners are widely used in mechanical structures primarily owing to their easy disassembly for maintenance and low cost. However, the...     

Heat Transfer Characteristics of Flood-type Evaporator Using R22 and R134a for Fishing Vessels

ABSTRACT

Most of fishing vessels pour plain ice into fish storages to maintain freshness of catches, which causes varying storage temperatures and changes in the salinity, and damages in catches. In contrast, seawater cooling systems that directly chill the seawater in the storage provide seawater with a constant temperature and salinity. Furthermore, the application of a flood-type evaporator enables the size of the system to be reduced due to the enhanced heat transfer performance of the evaporator. This study conducts experimental research on the boiling heat transfer characteristics of flood-type evaporators under various operating conditions. The test section of the experiment consists of the flood-type evaporator including tubes made of three different materials and having two different shapes, and R134a and R22 are used. As a result, low-fin tubes were found to present a higher heat transfer coefficient than that of the plain tube. Aluminum-brass low-fin tubes exhibited relatively 4.5% higher heat transfer coefficient than that of copper-nickel low-fin tubes when R22 was used, and relatively 5.3% higher value when the R134a was used. When R22 was used with an aluminum-brass low-fin tube, the heat transfer coefficient was relatively 6.9% higher than that when using R134a.     

Thermal characteristics of unsaturated dicarboxylic acid durable press finishing systems

Thermoanalytical (TA) studies including differential scanning calorimetric (DSC) and thermogravimetric (TG) analyses were carried out to measure characteristics of dried mixtures based on two unsaturated polycarboxylic acids. Model 9% treatment (pad) solutions of maleic (M) and/or itaconic (I) acid, with and without potassium peroxydisulfate (K) as the free-radical initiator, were prepared with sodium hypophosphite (H) as the catalyst and vacuum oven-dried. DSC thermograms varied with each component; even the presence of a small amount of component K was evident. TG residue production and maximum rates of weight loss were the most useful thermal parameters. Residue/rate factors, used previously as predictors, were calculated. Previous studies indicated that high residues and low rates were indicators of combinations of reactants that resulted in good durable press treatments for fabrics. Residue/rate factors were used to rank the six mixtures that reflect actual fabric treatment combinations: MH, IH, MIH, and those same three with the initiator present. Rankings indicated that the presence of the initiator significantly increased the residue/rate factor for IHK and for MIHK. The presence of the initiator appears more beneficial to itaconic acid than to maleic acid. The rankings by the TA predictor agreed with textile properties measuring appearance and strength. © 1994 John Wiley & Sons, Inc.     

Subband-based blind signal separation for noisy speech recognition

A method for directly extracting clean speech features from noisy speech is proposed. This process is based on independent component analysis (ICA) and a new feature analysis technique for reducing the computational complexity of the frequency domain ICA. For noisy speech signals recorded in real environments, this method yielded a considerable performance improvement     

二醛和一氯均三嗪活性染料实现棉一浴染色和无甲醛耐久性压烫整理

所谓一浴染色和耐久性压烫整理 (简称ODF)是指将染料和整理剂放到同一浴液中进行。该法的优点是降低能耗 ,缩短生产时间 ,减少染化剂和整理剂 ,减轻废水排放量。此外 ,也可以减少因交联而给棉染色带来的问题。由于甲醛具有潜在的致癌作用 ,棉在压烫整理中广泛采用丁烷四甲酸、柠檬酸以及马来酸和衣康酸的混合物等多元羧酸。在一浴法中这些多元羧酸往往可以和活性染料以及直接染料同时并用 ,处理后色光和染色牢度极佳。但是由于多元羧酸一浴法通常需要在较高的温度 (高于 1 80℃ )下才能将多元酸和染料同时固着在棉织物上 ,而且在多元羧酸…     

DeepLip: block-based lip pixel detection by deep neural networks

This paper presents an effective lip pixel detection method based on blocks and deep neural networks. Since only-rough localization of a pair of lips is a trivial task, we use a rectangle that loosely bounds two lips as an input region of interest for lip detection. For each pixel in the rectangle region we generate a block whose center is at the pixel, and the pixel is classified into either a lip or non-lip pixel by exploiting the pixels in the block. Deep neural networks are trained using a sufficient number of labeled blocks obtained from a quite tractable number of labeled images. As a result, lip pixels are detected with high accuracy despite negligible labeling effort. Experimental results demonstrate the effectiveness of the presented method. We show that even single-minute training can outperform the mouth map with the best threshold.     

FPGA implementation of ICA algorithm for blind signal separation and adaptive noise canceling

An field programmable gate array (FPGA) implementation of independent component analysis (ICA) algorithm is reported for blind signal separation (BSS) and adaptive noise canceling (ANC) in real time. In order to provide enormous computing power for ICA-based algorithms with multipath reverberation, a special digital processor is designed and implemented in FPGA. The chip design fully utilizes modular concept and several chips may be put together for complex applications with a large number of noise sources. Experimental results with a fabricated test board are reported for ANC only, BSS only, and simultaneous ANC/BSS, which demonstrates successful speech enhancement in real environments in real time.