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Selected AbstractsA simple instant-estimation method for time-average quantities of single-phase power and application to single-phase power grid connection by inverterELECTRICAL ENGINEERING IN JAPAN, Issue 2 2007Shinji Shinnaka Abstract This paper presents and analyzes a new simple instant-estimation method for time-average quantities such as rms values of voltage and current, active and reactive powers, and power factor for single-phase power with the fundamental component of constant or nearly constant frequency by measuring instantaneous values of voltage and current. According to the analyses, the method can instantly estimate time-average values with accuracy of the fundamental frequency, and estimation accuracy of the power factor is about two times better than that of voltage, current, and powers. The instant-estimation method is simple and can be easily applied to single-phase power control systems that are expected to control instantly and continuously power factor on a single-phase grid by inverter. Based on the proposed instant-estimation method, two methods for such power control systems are also proposed and their usefulness is verified through simulations. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(2): 34,43, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20236 [source] A new evaluation technique for the detection of impurities in purified proteins via CE with native UV-LIFELECTROPHORESIS, Issue 2 2010Audrey Rodat Abstract An analytical methodology for quality control analyses of IgG and their impurities is presented using a new UV-LIF (266,nm) detector inside the cassette of a CE instrument and its performance was evaluated. The observed sensitivity was very close to that obtained by silver staining of slab gels (LOD of 25,ng/mL), while the sensitivity of the analysis is 80 times better than with CE/UV absorption (214,nm). Examples of the analysis of pharmaceutical and other commercial IgGs are provided and the kinetics of the reduction of IgG by ,-mercaptoethanol is reported, demonstrating the ease of performing the analysis. [source] Optimization of the electrokinetic supercharging preconcentration for high-sensitivity microchip gel electrophoresis on a cross-geometry microchipELECTROPHORESIS, Issue 14 2004Zhongqi Xu Abstract We developed a novel on-line preconcentration procedure for microchip gel electrophoresis (MCGE), which enables application of electrokinetic supercharging (EKS) for highly sensitive detection of DNA fragments on a cross-geometry microchip. In comparison with conventional pinched injection using the cross microchip, the present approach allows loading a much larger amount of the sample by taking advantage of a newly developed operational mode. In order to obtain high preconcentration effect and prevent splitting of an enriched sample into subchannels, i.e., off the detector range, effects of the voltage applied on the reservoirs and the time of isotachophoretic preconcentration were examined. The optimal balance between the voltage and time was found for a high-sensitivity analysis of DNA fragments. After experimental optimization the detection limit of a 150 bp fragment was as low as 0.22 mg/L (S/N = 3) that is 10 times better than using the conventional pinched injection. [source] Auditory orienting and inhibition of return in mild traumatic brain injury: A FMRI studyHUMAN BRAIN MAPPING, Issue 12 2009Andrew R. Mayer Abstract The semiacute phase of mild traumatic brain injury (mTBI) is associated with deficits in the cognitive domains of attention, memory, and executive function, which previous work suggests may be related to a specific deficit in disengaging attentional focus. However, to date, there have only been a few studies that have employed dynamic imaging techniques to investigate the potential neurological basis of these cognitive deficits during the semiacute stage of injury. Therefore, event-related functional magnetic resonance imaging was used to investigate the neurological correlates of attentional dysfunction in a clinically homogeneous sample of 16 patients with mTBI during the semiacute phase of injury (<3 weeks). Behaviorally, patients with mTBI exhibited deficits in disengaging and reorienting auditory attention following invalid cues as well as a failure to inhibit attentional allocation to a cued spatial location compared to a group of matched controls. Accordingly, patients with mTBI also exhibited hypoactivation within thalamus, striatum, midbrain nuclei, and cerebellum across all trials as well as hypoactivation in the right posterior parietal cortex, presupplementary motor area, bilateral frontal eye fields, and right ventrolateral prefrontal cortex during attentional disengagement. Finally, the hemodynamic response within several regions of the attentional network predicted response times better for controls than for patients with mTBI. These objective neurological findings represent a potential biomarker for the behavioral deficits in spatial attention that characterize the initial recovery phase of mTBI. Hum Brain Mapp, 2009. © 2009 Wiley-Liss, Inc. [source] A precise boundary element method for macromolecular transport propertiesJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 9 2004Sergio Aragon Abstract A very precise boundary element numerical solution of the exact formulation of the hydrodynamic resistance problem with stick boundary conditions is presented. BEST, the Fortran 77 program developed for this purpose, computes the full transport tensors in the center of resistance or the center of diffusion for an arbitrarily shaped rigid body, including rotation-translation coupling. The input for this program is a triangulation of the solvent-defined surface of the molecule of interest, given by Connolly's MSROLL or other suitable triangulator. The triangulation is prepared for BEST by COALESCE, a program that allows user control over the quality and number of triangles to describe the surface. High numerical precision is assured by effectively exact integration of the Oseen tensor over triangular surface elements, and by scaling the hydrodynamic computation to the precise surface area of the molecule. Efficiency of computation is achieved by the use of public domain LAPACK routines that call BLAS Level 3 hardware-optimized subroutines available for most processors. A protein computation can be done in less than 10 min of CPU time in a modern Pentium IV processor. The present work includes a complete analysis of the sources of error in the numerical work and techniques to eliminate these errors. The operation of BEST is illustrated with applications to ellipsoids of revolution, and Lysozyme, a small protein. The typical numerical accuracy achieved is 0.05% compared to analytical theory. The numerical precision for a protein is better than 1%, much better than experimental errors in these quantities, and more than 10 times better than traditional bead-based methods. © 2004 Wiley Periodicals, Inc. J Comput Chem 9: 1191,1205, 2004 [source] Synthesis and electroluminescent properties of fluorene-based copolymers containing electron-withdrawing thiazole derivativesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 21 2008In Hwan Jung Abstract We synthesized two fluorene-based copolymers poly[(2,5-bis(4-hexylthiophen-2-yl)thiazolo[5,4-day]thiazole-5,5,-diyl)-alt-(9,9,-dioctylfluorene-2,7-diyl)] (PF-TTZT), and poly[(5,5,-bis(4-hexylthiophen-2-yl)-2,2,-bithiazole-5,5,-diyl)-alt-(9,9,-dioctylfluorene-2,7-diyl)] (PF-TBTT), which contain the electron-withdrawing moieties, thiazolothiazole, and bithiazole, respectively. Through electrochemical studies, we found that these two polymers exhibit stable reversible oxidation and reduction behaviors. Moreover, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of PF-TBTT are lower than those of PF-TTZT, and the bandgap of PF-TBTT is smaller than that of PF-TTZT. Thus the bithiazole moiety in PF-TBTT is more electron-withdrawing than the thiazolothiazole moiety in PF-TTZT. Light-emitting devices with indium tin oxide (ITO)/poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate)(PEDOT)/polymer/bis(2-methyl-8-quinolinato)-4-phenylphenolate aluminum (BAlq)/LiF/Al configurations were fabricated. The performance of the PF-TBTT device was found to be almost three times better than that of the PF-TTZT device, which is because electron injection from the cathode to PF-TBTT is much easier than for PF-TTZT. We also investigated the planarity and frontier orbitals of the electron donor-acceptor (D-A) moieties with computational calculations using ab initio Hartree,Fock with the split-valence 6-31G* basis set. These calculations show that TBTT has a more nonplanar structure than TTZT and that the bithiazole moiety is more electron-withdrawing than thiazolothiazole. These calculations are in good agreement with the experimental results. © Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7148,7161, 2008 [source] Magnitude image CSPAMM reconstruction (MICSR)MAGNETIC RESONANCE IN MEDICINE, Issue 2 2003Moriel NessAiver Abstract Image reconstruction of tagged cardiac MR images using complementary spatial modulation of magnetization (CSPAMM) requires the subtraction of two complex datasets to remove the untagged signal. Although the resultant images typically have sharper and more persistent tags than images formed without complementary tagging pulses, handling the complex data is problematic and tag contrast still degrades significantly during diastole. This article presents a magnitude image CSPAMM reconstruction (MICSR) method that is simple to implement and produces images with improved contrast and tag persistence. The MICSR method uses only magnitude images , i.e., no complex data , but yields tags with zero mean, sinusoidal profiles. A trinary display of MICSR images emphasizes their long tag persistence and demonstrates a novel way to visualize myocardial deformation. MICSR contrast and contrast-to-noise ratios (CNR) were evaluated using simulations, a phantom, and two normal volunteers. Tag contrast 1000 msec after the R wave trigger was 3.0 times better with MICSR than with traditional CSPAMM reconstruction techniques, while CNRs were 2.0 times better. Magn Reson Med 50:331,342, 2003. © 2003 Wiley-Liss, Inc. [source] Bayesian galaxy shape measurement for weak lensing surveys , II.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2008Application to simulations ABSTRACT In this paper, we extend the Bayesian model fitting shape measurement method presented in Miller et al., and use the method to estimate the shear from the Shear TEsting Programme simulations (STEP). The method uses a fast model fitting algorithm that uses realistic galaxy profiles and analytically marginalizes over the position and amplitude of the model by doing the model fitting in Fourier space. This is used to find the full posterior probability in ellipticity. The shear is then estimated in a Bayesian way from this posterior probability surface. The Bayesian estimation allows measurement bias arising from the presence of random noise to be removed. In this paper, we introduce an iterative algorithm that can be used to estimate the intrinsic ellipticity prior and show that this is accurate and stable. We present results using the STEP parametrization that relates the input shear ,T to the estimated shear ,M by introducing a bias m and an offset c: ,M,,T=m,T+c. The average number density of galaxies used in the STEP1 analysis was 9 per square arcminute, for STEP2 the number density was 30 per square arcminute. By using the method to estimate the shear from the STEP1 simulations we find the method to have a shear bias of m= 0.006 ± 0.005 and a variation in shear offset with point spread function type of ,c= 0.0002. Using the method to estimate the shear from the STEP2 simulations we find that the shear bias and offset are m= 0.002 ± 0.016 and c=,0.0007 ± 0.0006, respectively. In addition, we find that the bias and offset are stable to changes in the magnitude and size of the galaxies. Such biases should yield any cosmological constraints from future weak lensing surveys robust to systematic effects in shape measurement. Finally, we present an alternative to the STEP parametrization by using a quality factor that relates the intrinsic shear variance in a simulation to the variance in shear that is measured and show that the method presented has an average of Q, 100 which is at least a factor of 10 times better than other shape measurement methods. [source] What can we learn on the thermal history of the Universe from future cosmic microwave background spectrum measurements at long wavelengths?MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2003C. Burigana ABSTRACT We analyse the implications of future observations of the cosmic microwave background (CMB) absolute temperature at centimetre and decimetre wavelengths, where both ground, balloon and space experiments are currently under way to complement the accurate COBE/FIRAS data available at ,, 1 cm. Our analysis shows that forthcoming ground and balloon measurements will allow a better understanding of free,free distortions but will not be able to significantly improve the constraints already provided by the FIRAS data on the possible energy exchanges in the primeval plasma. The same holds even for observations with sensitivities up to ,10 times better than those of forthcoming experiments. Thus, we have studied the impact of very high-quality data, such as those, in principle, achievable with a space experiment such as the Diffuse Microwave Emission Survey (DIMES) planned to measure the CMB absolute temperature at 0.5 ,,, 15 cm with a sensitivity of ,0.1 mK, close to that of FIRAS. We have demonstrated that such high-quality data would improve by a factor of ,50 the FIRAS results on the fractional energy exchanges, ,,/,i, associated with dissipation processes possibly occurred in a wide range of cosmic epochs, at intermediate and high redshifts (yh, 1), and that the energy dissipation epoch could also be significantly constrained. By jointly considering two dissipation processes occurring at different epochs, we demonstrated that the sensitivity and frequency coverage of a DIMES -like experiment would allow one to accurately recover the epoch and the amount of energy possibly injected into the radiation field at early and intermediate epochs even in the presence of a possible late distortion, while the constraints on the energy possibly dissipated at late epochs can be improved by a factor of ,2. In addition, such measurements can provide an independent and very accurate cross-check of FIRAS calibration. Finally, a DIMES -like experiment will be able to provide indicative independent estimates of the baryon density: the product ,bH20 can be recovered within a factor of ,2,5 even in the case of (very small) early distortions with ,,/,i, (5,2) × 10,6. On the other hand, for ,b (H0/50)2, 0.2, an independent baryon density determination with an accuracy at , per cent level, comparable to that achievable with CMB anisotropy experiments, would require an accuracy of ,1 mK or better in the measurement of possible early distortions but up to a wavelength from , few × dm to ,7 dm, according to the baryon density value. [source] Improved imaging resolution in desorption electrospray ionization mass spectrometry,RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 17 2008Vilmos Kertesz The imaging resolution of desorption electrospray ionization mass spectrometry (DESI-MS) was investigated using printed patterns on paper and thin-layer chromatography (TLC) plate surfaces. Resolution approaching 40,µm was achieved with a typical DESI-MS setup, which is approximately 5 times better than the best resolution reported previously. This improvement was accomplished with careful control of operational parameters (particularly spray tip-to-surface distance, solvent flow rate, and spacing of lane scans). In addition, an appropriately strong analyte/surface interaction and uniform surface texture on the size scale no larger than the desired imaging resolution were required to achieve this resolution. Overall, conditions providing the smallest possible effective desorption/ionization area in the DESI impact plume region and minimizing the analyte redistribution on the surface during analysis led to improved DESI-MS imaging resolution. Published in 2008 by John Wiley & Sons, Ltd. [source] Comparison of three methods for the extraction of arsenic compounds from the NRCC standard reference material DORM-2 and the brown alga Hijiki fuziformeAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 6 2001Doris Kuehnelt Abstract The NRCC standard reference material DORM-2 and the marine brown alga Hijiki fuziforme were extracted with water, methanol/water (9,+,1), and 1.5 M orthophosphoric acid. The extracts from DORM-2 were analyzed by HPLC,ICP-MS for arsenobetaine, arsenocholine, trimethylarsine oxide, and the tetramethylarsonium cation and the extracts from H. fuziforme for arsenous acid, arsenic acid, dimethylarsinic acid, methylarsonic acid, and four arsenoriboses. Almost no differences between the three extractants were observed when DORM-2 was investigated. Only arsenobetaine was slightly better extracted with 1.5 M orthophosphoric acid or methanol/water (9,+,1) than with water. The sum of all extractable compounds (arsenobetaine, the tetramethylarsonium cation, and a formerly unknown compound recently identified as the trimethyl(2-carboxyethyl)arsonium ion) accounted for 94% of the total arsenic when 1.5 M orthophosphoric acid was used, for 92% when methanol/water (9,+,1) was used, and for 87% when water was used. Significant differences in the extraction yields obtained for the alga were observed for arsenic acid and one of the arsenoriboses (,glycerol-ribose'). Orthophosphoric acid removed twice as much of this ribose from the algal material than water and three times more than methanol/water (9,+,1). Arsenic acid was 1.2 times better extracted with orthophosphoric acid than with water and ten times better than with methanol/water (9,+,1). Almost no differences in the extraction yields were found for dimethylarsinic acid and the other three riboses. Orthophosphoric acid extracted 76%, water 65%, and methanol/water 33% of the total arsenic from H. fuziforme. Copyright © 2001 John Wiley & Sons, Ltd. [source] | |||||||||||||