A current-mode bit-block circuit applicable to low-voltage, low-power pipeline video-speed A/D converters

This paper describes a study to determine if a current-mode circuit is useful as an analog circuit technique for realizing submicron mixed analog-and-digital MOS LSIs. To examine this, we designed and circuit simulated a new current-mode ADC bit-block for a 3 V, 10-bit level, 20 MHz ADC with a pipeline architecture and with full current-mode approach. A new precision current-mode sample-and-hold circuit which enables operation of a bit block at a clock speed of 20 MHz was developed. Current mismatches caused by the poor output impedance of a device were also decreased by adopting a cascode configuration throughout the design. Operation with a 3 V power supply and a 20 MHz clock speed in a 3-bit A/D configuration was verified through circuit simulation using standard CMOS 0.6 m device parameters. Gain error, mismatch of current, and linearity of the bit block with changing threshold voltage of a device were carefully examined. The bit block has a gain error of 0.2% (10-bit level), a linearity error of less than 0.1% (more than 10-bit level), and a current mismatch of DAC current sources in a bit cell of 0.2 to 0.4% (more than 8-bit level) with a 3 V power supply and 20 MHz clock speed. An 8-to 9-bit video-speed pipeline ADC can be realized without calibration. This confirms that the current-mode approach is effective.     

The robustness of a Nash equilibrium simulation model: Game-theoretic approach using variable metric projection method

This paper proposes a Nash equilibrium model that applies continuous time replicator dynamics to the analysis of oligopoly markets. The robustness of the proposed simple Nash equilibrium model under the simultaneous constraints of allocation of product and market share using a simulation method to derive an optimal solution for production decisions by rival firms in oligopoly markets is tested by changing profit and cost function parameters, as well as the initial production values and market shares of the firms examined in this study. The effects of differences in conjectural variation and initial allocation of market share on the convergent values are considered, particularly in the case of corner solutions. This approach facilitates the understanding of the robustness of attaining equilibrium in an oligopoly market.     

Adsorptive Recovery of Palladium(II) and Platinum(IV) on the Chemically Modified-Microalgal Residue

A biomass waste of microalgae was chemically modified by immobilizing the functional group of polyethyleneimine to prepare a new type of adsorbent. The adsorption test revealed that this adsorbent exhibited remarkably high selectivity for Pd(II) and Pt(IV) over base metal ions in HCl solution. From the adsorption isotherm, its maximum adsorption capacity for Pd(II) and Pt(IV) was evaluated as 2.0 and 0.8 mmol/g, respectively. This adsorbent also exhibited high affinity and selectivity for Pd(II) and Pt(IV) even in the presence of high concentrations of base metals in actual leach liquor.     

Improvement of gas barrier property of polyolefins by diamond‐like carbon deposition and photografting polymerization

The gas barrier properties of isotactic polypropylene (iPP) and high‐density polyethylene (HDPE) are both significantly improved by diamond‐like carbon (DLC) deposition and photografting polymerization using acrylic acid (AA) monomers. In fact, the gas barrier properties can be highly improved just by DLC or by AA‐photografting polymerization. The improvement observed by AA‐photografting polymerization is more pronounced than that by DLC deposition in our general experimental condition. In more detail, the oxygen barrier property of DLC‐deposited and AA‐grafted iPP is considerably improved by ～10 times when compared with that of neat iPP. As for HDPE, the oxygen barrier property is enhanced by nearly six times through DLC deposition and photografting polymerization. By observing the surfaces, 30 nm layer of DLC and 1.0 μm of AA‐grafted layer are firmly constructed on the polyolefins, which should contribute to the enhancement of the oxygen barrier property. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

PredNTS: Improved and Robust Prediction of Nitrotyrosine Sites by Integrating Multiple Sequence Features

Nitrotyrosine, which is generated by numerous reactive nitrogen species, is a type of protein post-translational modification. Identification of site-specific nitration modification on tyrosine is a prerequisite to understanding the molecular function of nitrated proteins. Thanks to the progress of machine learning, computational prediction can play a vital role before the biological experimentation. Herein, we developed a computational predictor PredNTS by integrating multiple sequence features including K-mer, composition of k-spaced amino acid pairs (CKSAAP), AAindex, and binary encoding schemes. The important features were selected by the recursive feature elimination approach using a random forest classifier. Finally, we linearly combined the successive random forest (RF) probability scores generated by the different, single encoding-employing RF models. The resultant PredNTS predictor achieved an area under a curve (AUC) of 0.910 using five-fold cross validation. It outperformed the existing predictors on a comprehensive and independent dataset. Furthermore, we investigated several machine learning algorithms to demonstrate the superiority of the employed RF algorithm. The PredNTS is a useful computational resource for the prediction of nitrotyrosine sites. The web-application with the curated datasets of the PredNTS is publicly available.     

Short‐term load forecasting using informative vector machine

In this paper, a novel method is proposed for short‐term load forecasting, which is one of the important tasks in power system operation and planning. The load behavior is so complicated that it is hard to predict the load. The deregulated power market is faced with the new problem of an increase in the degree of uncertainty. Thus, power system operators are concerned with the significant level of load forecasting. Namely, probabilistic load forecasting is required to smooth power system operation and planning. In this paper, an IVM (Informative Vector Machine) based method is proposed for short‐term load forecasting. IVM is one of the kernel machine techniques that are derived from an SVM (Support Vector Machine). The Gaussian process (GP) satisfies the requirements that the prediction results are expressed as a distribution rather than as points. However, it is inclined to be overtrained for noise due to the basis function with N² elements for N data. To overcome this problem, this paper makes use of IVM that selects necessary data for the model approximation with a posteriori distribution of entropy. That has a useful function to suppress the excess training. The proposed method is tested using real data for short‐term load forecasting. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(2): 23– 31, 2009; Published online in Wiley InterScience ( www. interscience.wiley.com ). DOI 10.1002/eej.20693     

A 256-Mb multilevel flash memory with 2-MB/s program rate for massstorage applications

A 256-Mb flash memory is fabricated with a 0.25-μm AND-type memory cell and 2-bit/cell multilevel technique on a 138.6-mm² die. Parallel decoding of four memory threshold voltage levels to 2-bit logical values prevents throughput degradation due to multilevel operation. This parallel decoding has been achieved by sense latches and data latches connected to each bitline. Tight distribution of memory cell threshold voltage is essential to reliable multilevel operation. This chip has several measures to deal with the factors that widen the memory cell V_th. The effect of adjacent memory cell's V_th is eliminated by using an AND-type flash memory cell. An initial distribution width of 0.1 V is achieved. The wordline voltage, which has negative temperature dependency, compensates the positive dependency of memory cell V_th. In the -5-75°C range, memory threshold V_th deviation is reduced from the conventional 0.19-0.07 V. Conventionally, the number of programs without erase operation per one sector is limited by the limitations from program disturb. This chip introduced a new rewrite scheme, and this limit is increased from the conventional 10-2048+64 times/sector     

Metaiodobenzylguanidine and heart rate variability in heart failure

It is assumed that the low-frequency power (LF) of heart rate variability (HRV) increases with progress of congestive heart failure (CHF), therefore positively correlating with cardiac 123I-metaiodobenzylguanidine (MIBG) washout. It is demonstrated here that HRV, including normalized LF, correlated inversely with MIBG washout and positively with the ratio of heart-to-mediastinum MIBG activity in controls and CHF patients, whereas these correlations were not observed within CHF patients. Thus MIBG washout may increase and HRV including normalized LF may decrease with CHF, although the HRV and MIBG measures may not similarly change in proportion to the severity of the cardiac autonomic dysfunction in CHF.     

Selective recovery of gold by simultaneous adsorption–reduction using microalgal residues generated from biofuel conversion processes

BACKGROUND: This research provides a new approach to the effective use of microalgal biomass waste generated by biofuel conversion processes. In this study, a novel adsorbent for Au(III) recovery was prepared by treating microalgal residues with concentrated sulfuric acid. RESULTS: The prepared adsorbent, crosslinked microalgae, exhibited high affinity and selectivity for Au(III) over other precious and base metal ions in a hydrochloric acid medium. From the adsorption isotherms, the maximum adsorption capacity of the crosslinked microalgae for Au(III) was estimated to be 3.25 mol kg^?1 (640 g kg^?1), which was about eight times higher than the adsorption capacity of the microalgal residue. Microphotographs, scanning electron microscopy, and X‐ray diffraction confirmed the formation of metallic Au, suggesting that a redox reaction had taken place between the adsorbent and Au(III) ions during adsorption. Comparison of Fourier‐transform infrared spectra before and after adsorption indicated that hydroxyl groups as well as ether oxygen atoms in the crosslinked microalgae participated in the Au(III) uptake mechanism. It also suggested that the reduction of Au(III) to Au(0) was facilitated by hydroxyl groups in the crosslinked microalgae. CONCLUSION: The results presented in this paper are very promising for the practical use of microalgal residues for the recovery of Au(III) because of good selectivity and favorable adsorption capacity for Au(III). Copyright © 2011 Society of Chemical Industry