A Kinetic Study on the Electrodeposition of Fe-Zn-P Ternary Alloys

A kinetic study of electrodeposition of an Fe-Zn-P ternary alloy on steel in a chloride solution was carried out using a rotating disc geometry. The deposition rates of iron and zinc on steel are controlled by the rates of both electrochemical reaction and mass transfer through a diffusion layer, and that of phosphorus is controlled by the rate of electrochemical reaction. Zinc content in the Fe-Zn-P alloy increases with increased stirring speed and voltage, however, iron content decreases with increased stirring speed and voltage. Phosphorus content is almost constant with an increase of stirring speed in lower voltage ranges and decreases slightly with increased stirring speed in the higher voltage ranges.     

Origin of bistability in polyfluorene-based organic bistable devices

This study examined the origin of bistability in polyfluorene (PFO)-based organic bistable memory devices (OBDs) by changing the bulk properties of PFO and metal electrodes. Two different PFOs with and without internal trap sites and two Al and Au electrodes were used. Bistability was induced in all devices when Al was deposited on PFO. On the other hand, bistable switching was observed only in the PFO device with internal trap sites when Au was deposited on PFO. Therefore, both the formation of internal trap sites and an organic–metal interface are essential for bistability in PFO-based OBDs.     

Maximum Likelihood Training and Adaptation of Embedded Speech Recognizers for Mobile Environments

For the acoustic models of embedded speech recognition systems, hidden Markov models (HMMs) are usually quantized and the original full space distributions are represented by combinations of a few quantized distribution prototypes. We propose a maximum likelihood objective function to train the quantized distribution prototypes. The experimental results show that the new training algorithm and the link structure adaptation scheme for the quantized HMMs reduce the word recognition error rate by 20.0%.     

Origin of bistable memory characteristics of organic light-emitting diodes with LiF/Al cathode

Bistable memory performances of organic light-emitting diodes (OLEDs) with LiF/Al cathode were investigated and the origin of bistability was studied. LiF was essential to get stable memory performances in OLEDs and on/off ratio was improved by more than 50 times by using LiF/Al instead of Al cathode. High on/off ratio over 1000 was obtained from switching test and the multilevel switching of organic light-emitting bistable devices (OLEBDs) was realized by changing the writing voltage of OLEBDs. AlF₃ formation at the interface during evaporation of Al was proposed as the main mechanism for bistability of OLEBDs.     

Lifetime study of red phosphorescent organic light-emitting diodes with a double doping structure

The lifetime of red phosphorescent organic light-emitting diodes with a double doping structure was studied. Green and red phosphorescent dopants were co-doped in the emitting layer and the lifetime of the red devices with the doubly doped emitting structure was dependent on the doping concentration of the green dopant due to the energy transfer from the green dopant to the red dopant.     

Micromachined filters on synthesized substrates

Effective high-frequency spectrum usage requires high-performance filters to have a sharp cutoff frequency and high stopband attenuation. Stepped-impedance low-pass designs achieve this function best with large ratios of high-to-low-impedance values. In high-index materials, such as Si (11.7) and GaAs (12.9), however these high-to-low-impedance ratios are around five, thereby significantly limiting optimum filter performance. This paper characterizes the use of Si micromachining for the development of synthesized substrates, which, when utilized appropriately, can further reduce the low-impedance value or increase the high-impedance value. Both designs have demonstrated high-to-low-impedance ratios that are 1.5-2 times larger than conventional techniques     

N-nitrosamine reduction in salted and fermented anchovy sauce by ionizing irradiation

Salted and fermented anchovy sauce spiked with or without N-nitrosodimethylamine (NDMA) and N-nitrosopyrrolidine (NPYR) was irradiated at 0, 5, 10, 15 and 20 kGy. NDMA and NPYR reduction by irradiation was not observed in non-spiked samples at 0 week, while a significant reduction was observed after 4 weeks of storage at 15 °C (P<0.05). In N-nitrosamine spiked samples, a positive effect of irradiation on NDMA and NPYR reduction was observed. NDMA and NPYR levels were decreased by irradiation at 5 kGy or above after storage. Therefore, gamma irradiation has a possibility to reduce N-nitrosamines in salted and fermented anchovy sauce.     

Gamma irradiation and ozone treatment for inactivation of Escherichia coli O157:H7 in culture media

A study was conducted to investigate the reduction and elimination of Escherichia coli O157:H7 by the effects of gamma irradiation and ozone treatment. Log phase cells were found to be more sensitive to gamma irradiation than stationary phase cells. E. coli O157:H7 was found to be considerably more resistant to irradiation at -18 degrees C than at 20 degrees C. The D values for this organism for treatment with ozone in tryptic soy agar were higher than those for treatment with ozone in phosphate buffer. Gamma irradiation at a dose of 1.5 kGy or ozone treatment at a concentration of 3 to 18 ppm for 20 to 50 min was required to assure the elimination of E. coli O157:H7.     

Robust Voice Activity Detection Using the Spectral Peaks of Vowel Sounds

This letter proposes the use of vowel sound detection for voice activity detection. Vowels have distinctive spectral peaks. These are likely to remain higher than their surroundings even after severe corruption. Therefore, by developing a method of detecting the spectral peaks of vowel sounds in corrupted signals, voice activity can be detected as well even in low signal‐to‐noise ratio (SNR) conditions. Experimental results indicate that the proposed algorithm performs reliably under various noise and low SNR conditions. This method is suitable for mobile environments where the characteristics of noise may not be known in advance.     

A Closed‐Form Solution of Linear Spectral Transformation for Robust Speech Recognition

The maximum likelihood linear spectral transformation (ML‐LST) using a numerical iteration method has been previously proposed for robust speech recognition. The numerical iteration method is not appropriate for real‐time applications due to its computational complexity. In order to reduce the computational cost, the objective function of the ML‐LST is approximated and a closed‐form solution is proposed in this paper. It is shown experimentally that the proposed closed‐form solution for the ML‐LST can provide rapid speaker and environment adaptation for robust speech recognition.